Note: Descriptions are shown in the official language in which they were submitted.
CA 02286490 1999-10-29
PRIMER SYSTEM FOR AGRICULTURAL PRODUCT DISTRIBUTION MACHINES
FIELD OF INVENTION
The present invention relates to a primer system for agricultural product
distribution
machines, such as air seeders, precision planters, sprayers, and the like.
BACKGROUND OF THE INVENTION
Agricultural machines used for applying product over a field will be referred
to herein
as agricultural product distribution machines. Such machines include seeders,
fertilizers,
planters, sprayers, and the like.
Agricultural product distribution machines must apply the product to be
distributed
evenly across the entire field. With a fertilizer distributing machine, for
example, it is
important that each area of the field receive, as accurately as possible, the
required amount
of fertilizer. The practice of averaging product requirements for an entire
field is common.
However, averaging product requirements may result in over fertilizing some
areas of the
field and under fertilizing others.
Technological advances now enable farmers to obtain greater accuracy in
product
application. For example, yield monitors used in association with a combine
measure the
amount of grain being harvested as the grain is sent to the bin in the
combine. The actual
yield of the best and poorest areas can be observed on the monitor. In
addition,
Global Positioning Systems (GPS) can provide information as to the exact
position of the
machinery in the field. Yield monitors combined with a GPS receiver, are used
to plot yield
maps and identify reasons why certain areas have low or high yields, which may
be related
to nutrient differences. With this information, farmers can then determine
whether a certain
part of the field might need more fertilizer, less fertilizer or should be
treated with a different
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farming method. Farmers can then apply fertilizer, herbicides, and seed at the
rate needed
for a particular soil site.
Variable rate systems have been developed to allow operators of agricultural
product
distribution machines to vary the application rate of the product without
leaving the tractor
cab. Several manufacturers of agricultural equipment offer variable rate drive
mechanisms
on their machines. One variable rate hydraulic drive control, disclosed in
Canadian patent
application No. 2,221,403, essentially consists of an electric motor that
provides a rotational
drive rate to a hydraulic motor, which controls the product metering
mechanism. The
electric motor input varies with ground speed, thus providing a consistent
rate of metering.
Other variable rate drive mechanisms are known.
A typical agricultural seeder includes a product bin and a product
distribution system.
The product distribution system generally includes a series of hoses and a
manifold. Product
is dispensed from the bin into the distribution system through a dispensing
mechanism, e.g.,
a metering wheel, at a rate related to the desired application rate of the
product onto the field.
The dispensing mechanism is typically driven by a variable rate drive system.
All of the above prior art systems have a product dispensing rate related to
the ground
speed (also known in the art as forward speed) of the agricultural product
distribution
machine. As the agricultural product distribution machine travels across the
field, a sensor
detects the ground speed. The variable rate drive mechanism drives the
dispensing
mechanism accordingly. As the ground speed varies, the dispensing rate varies
to maintain
a consistent distribution of product.
A common characteristic of many variable rate systems is that the variable
rate drive
metering mechanism will begin operating only after a minimum ground speed is
detected by
the sensors, in order to overcome detection errors. For example, a minimum
speed of
approximately 2 miles per hour is chosen with some known seeders. If a
stationary seeder
is accelerated to an operating speed, it could take about 2 to 10 seconds for
the minimum
ground speed to be detected and the metering mechanism to be activated. By
this time, the
seeder could have travelled up to 30 feet in the field without dispensing any
seed. After the
meter starts dispensing seed, the operator has to retrace his path to seed
that area. The time
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lag between movement of the seeder and the dispensing of seed is inefficient,
time
consuming, and can cause seeding errors in the field. Other systems, do not
require the
detection of a minimum ground speed in order for their metering mechanisms to
start
operating, but there is still a time lag for the product to reach the ground,
leading to the same
problems. Unused or inaccurately seeded land is wasteful of space and money.
It is
advantageous for farmers, especially row crop farmers, to use all available
land. Accurately
dispensed seeds achieve better yields. Similar problems are associated with
other
agricultural product distribution machines.
In some circumstances, agricultural product distribution machines must be
backed
into a corner of a field before they can be moved forward and the product
distribution
process, such as seeding, begins. In such situations, an area may be left
unseeded as there
is no opportunity for the operator to retract his path.
Similar problems arise when the agricultural product distribution machine may
have
to slow down below the minimum speed during the product dispensing process.
SUMMARY OF THE INVENTION
The present invention relates to a primer system for agricultural product
distribution
machines.
According to the invention, there is provided an agricultural product
distribution
machine comprising: storage means for storing a quantity of agricultural
product to be
distributed; conveying means for conveying agricultural product from the
storage means to
the ground surface; and control means for controlling the rate of transfer of
the agricultural
product from the storage means through the conveying means for distribution to
the ground,
the control means comprising: an regular operation system for automatically
controlling the
transfer of agricultural product at a rate dependent on process specific
parameters; and a
bypass system for controlling the transfer of agricultural product at a pre-
determined rate.
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According to the invention, there is further provided an air seeder
comprising:
storage means for storing a quantity of seed to be distributed; conveying
means for
conveying seed by way of air flow from the storage means through the ground
surface; and
control means for controlling the rate of transfer of the seed from the
storage means through
the conveying means for distribution to the ground, the control means
comprising: a regular
operation system for automatically controlling the transfer of seed at a rate
dependent on
process specific parameters; and a bypass system for controlling the transfer
of seed at a
pre-determined rate.
According to the invention, there is further provided a precision planter
comprising:
storage means for storing a quantity of seed to be distributed; conveying
means for
conveying seed from the storage means to the ground surface; and control means
for
controlling the rate of transfer of the seed from the storage means through
the conveying
means for distribution to the ground, the control means comprising: a regular
operation
system for automatically controlling the transfer of seed at a rate dependent
on process
specific parameters; and a bypass system for controlling the transfer of seed
at a
pre-determined rate.
According to the invention, there is further provided a sprayer comprising:
storage
means for storing a quantity of fluid to be distributed; conveying means for
conveying fluid
from the storage means to the ground surface; and control means for
controlling the rate of
transfer of the fluid from the storage means through the conveying means for
distribution to
the ground, the control means comprising: a regular operation system for
automatically
controlling the transfer of fluid at a rate dependent on process specific
parameters; and a
bypass system for controlling the transfer of fluid at a pre-determined rate.
The agricultural product distribution machine may be, for example, an air
seeder, a
precision planter, a sprayer, or the like.
In one aspect of the invention, a primer system for agricultural product
distribution
machines, such as an agricultural air seeder, a precision planter, a sprayer,
or the like,
includes a tank or a bin for holding the product, a distribution system for
conveying and
distributing the product from the tank, and a driving mechanism for driving
the product from
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CA 02286490 1999-10-29
the tank into the distribution system at a certain rate. The driving mechanism
can run
automatically or can be selectively operated, based on commands received from
a
microcontroller. The microcontroller may receive signals from a user interface
and from
sensing equipment, such as a ground speed detector, a pressure sensor, a flow
metre, or the
like. In a regular mode of operation, the controller runs the driving
mechanism automatically
at a rate calculated based on the signals received from the above mentioned
systems. Most
agricultural machines have the automated mode of operation of the driving
mechanism,
conditioned by the ground speed of the tractor being higher than a minimum
speed. In a
bypass mode of operation, the driving mechanism can be selectively operated by
pressing
a primer button on the user interface. The primer button triggers a bypass
signal, instructing
the microcontroller to run the driving mechanism at a predetermined dispensing
rate,
regardless of other factors, such as the detected ground speed.
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 and
claims.
BRIEF DESCRIPTION OF THE DRAWINGS
The embodiments of the invention will now be described with reference to the
accompanying drawings, in which:
Figure 1 is a block diagram of a known agricultural product distribution
machine;
Figure 2 is a block diagram of a primer system for a agricultural product
distribution
machine in accordance with an embodiment the present invention;
Figure 3 is a block diagram of a control unit, in accordance with an
embodiment of
the primer system in Figure 2;
Figure 4 represents a basic air delivery system;
Figure 5 represents a metering mechanism of the air delivery system in
Figure3;
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CA 02286490 1999-10-29
Figure 6 is a block diagram of a primer system in accordance with an
embodiment
of the present invention, as it applies to seeders and planters;
Figure 7 is a flow chart showing the microcontroller function, as it applies
to seeders
and planters, in one embodiment of the invention;
Figure 8 represents a basic sprayer system;
Figure 9 is a block diagram of a primer system in accordance with an
embodiment
of the present invention, as it applies to sprayers; and
Figure 10 is a flow chart showing the microcontroller function, as it applies
to
sprayers, in one embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
Referring to Figure 1, a known product distribution machine 10 generally
includes
at least one tank or other storage means 15 for holding product, and a
distribution system or
other conveying means 25 to transmit the product to a desired location.
Product is passed
from the storage means 15 to the conveying means 25 by a driving mechanism 20.
For simplicity, the invention will be described next in the context of
agricultural
product distribution machines.
Referring now to Figure 2, an agricultural product distribution machine 10 in
accordance with the present invention includes a storage means 15, a conveying
means 25
and a driving mechanism 20. The driving mechanism 20 includes a control unit
16 to control
the rate of transfer of product from the storage means 15 to the conveying
means 25,
preferably according to the desired rate of product distribution over a ground
surface. The
control unit 16 controls a regular operation system 17 which automatically
transfers product
from the storage means 15 to the conveying means 25 at a rate dependent on
process specific
parameters. The control unit 16 also controls a bypass system 18 that
transfers product from
the storage means 15 into the distribution system 25 at a pre-determined rate.
Referring now to Figure 3, the control unit includes a microcontroller 30,
which
enables the driving mechanism 20 to run automatically or to be selectively
operated by an
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CA 02286490 1999-10-29
operator. Referring also to Figure 4, an embodiment of the invention is
illustrated in the
context of a agricultural product distribution machine 10, towed by a vehicle
(not shown) in
a field onto which product must be applied.
In one embodiment of the invention, the microcontroller 30 receives command
signals from a ground speed sensor 40, from a user interface 50 and from other
sensors 42.
In the embodiment in Figure 3, the other sensors 42 are optional and, if
present, they are part
of the bypass system 18 in Figure 2. One of the functions of the other sensors
42 is to
determine conditions in which the bypass system 18 should be active, and to
signal such
conditions to the microcontroller 30. An operational example of the other
sensors 42, within
the context of the embodiment of Figure 3, will be described later on.
The ground speed sensor 40 detects the ground speed or forward speed of the
agricultural product distribution machine 10, as the vehicle tows the
agricultural product
distribution machine 10 across a field.
The user interface 50 allows the operator to monitor and set various
parameters
relating to the process, such as application rate, location in the field,
implement widths,
calibration numbers, and the like. Some of the process parameters can be
changed through
controls or operator settings 55.
A primer input unit 60 comprising one or more buttons or switches on the user
interface 50, allows the operator to manually and selectively operate the
driving mechanism
20, as will be further described.
The operator settings 55 on the user interface 50 may be buttons or any other
input
means, such as keys on a keypad, switches, levers, or the like. The user
interface 50 is
positioned in such way that an operator can control the system 'on-the-go',
i.e., while the
agricultural product distribution machine 10 is travelling in the field. In a
preferred
embodiment, the user interface 50 comprises a display unit and a console unit
situated in the
cab of the vehicle towing the agricultural product distribution machine 10. In
an alternative
embodiment, the user interface is accessible from other locations remote from
the
agricultural product distribution machine 10.
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CA 02286490 1999-10-29
Referring to Figure 3, the ground speed and the data from the user interface
50 are
collectively referred to as rate data input 65. The rate data input 65 is
processed by the
microcontroller 30. Upon processing, the microcontroller 30 activates the
driving
mechanism 20 which, in turn, drives product from the tank 15 into the
distribution system
25 at a controlled rate output 70.
The driving mechanism 20 has at least two modes of operation, which are
designated
herein as the 'regular mode of operation' and the 'bypass mode of operation'.
During the 'regular mode of operation', the driving mechanism runs
automatically
at a dispensing rate calculated based on the detected ground speed, on the
operator settings,
and on other process specific parameters. Therefore, the controlled rate
output 70 varies with
the rate data input 65 to compensate for ground speed fluctuations and to
produce a
consistent application of the product onto the field.
In many cases, the driving mechanism 20 functions in its 'regular mode of
operation'
only when the detected ground speed is above a minimum speed. The value of the
minimum
ground speed is selected based on various considerations, and can even be set
at zero miles
per hour.
If desired, the operator can bypass the 'regular mode of operation' of the
driving
mechanism 20 by activating the driving mechanism 20 to dispense product at a
predetermined controlled rate output 70; this is the 'bypass mode of
operation'. The 'bypass
mode of operation' can be directly selected by the operator through the primer
input unit 60.
Alternatively, the operator can allow other sensors 42 to automatically
determine that
conditions necessitating the activation of the bypass mode are met and to send
bypass signals
to the microcontroller 30, indicating that the driving mechanism should be
activated in the
'bypass mode'. For simplicity, the 'bypass mode' will next be described in
detail only for
the case when its activation takes place directly, through the primer input
unit 60. However,
it will be appreciated by those skilled in the art that a similar mode of
functioning applies to
the case when the 'bypass mode ' is triggered by means of the other sensors
42.
By pressing a button, for example, on the primer input unit 60, the operator
initiates
a program that bypasses the input from the ground speed sensor 40 to the
driving mechanism
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CA 02286490 1999-10-29
20. In other words, by pressing a primer button on the user interface 50, a
bypass signal is
sent to the microcontroller 30, which is programmed to start the driving
mechanism 20 at a
predetermined rate or at a computed rate.
Since the 'regular mode of operation' of the driving mechanism 20 generally
depends
on the detection of a minimum ground speed, one usually engages the driving
mechanism
20 in the 'bypass mode of operation' when the ground speed is below the
minimum speed.
Among the situations when this condition occurs are: at the beginning of the
application
process when the vehicle is stationary, when the vehicle is stopped midfield,
when the
vehicle is backed into a corner, and when crossing waterways or the like.
In one embodiment, the operator may select from a plurality of predetermined
rates
at which the microcontroller 30 can run the driving mechanism 20, different
rates being
suited to particular situations. Each rate may have a corresponding primer
button on the
primer input unit 60 in the cab of the vehicle.
The invention will be described next in the context of three preferred
embodiments:
air seeding systems, precision planters, and sprayers. The person skilled in
the art will
recognize that the present invention may be embodied in other types of product
distribution
machines.
Air Seeders
Figures 4 and 5 depict an air seeder or air cart I 10 (which is an
agricultural product
distribution machine 10) embodying the present invention. The air cart 110
includes an air
distribution system 125 (which is a conveying means 25). The air cart 110 also
includes a
seeding tool 27, which may be a series of ground openers. The air distribution
system 125
includes a manifold 127, and in some embodiments a series of hoses. The air
cart 110 can
be attached to a vehicle, such as a tractor, or it can be built as an integral
part of a vehicle.
The air cart I10 includes one or more tanks 115 (which is a storage means 15)
to hold
products like seed and fertilizer. The air cart 110 also includes a driving
mechanism 20. The
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driving mechanism 20 includes a metering system 120 to deliver the appropriate
amount of
product to the air distribution system 125, and a fan 128.
The metering system 120 controls the dispensing rate of product from the tanks
115
into the air distribution system 125. The dispensing rate of the metering
system 120
determines the application rate of product onto the field.
Referring now to Figure 5, the metering system 120 includes a metering wheel
121
designed to dispense product at a predetermined rate. As product passes
through the
metering system 120, it is carried by airflow provided by the fan through the
manifold 127
to headers 129, where the product is split into several runs and then passes
through the
ground opener and into the furrow created by the opener.
The metering system 120 is driven automatically by a variable rate drive
mechanism.
In the case of a metering wheel, the variable rate drive mechanism will rotate
the metering
wheel at various rates. Many designs of variable rate drive mechanisms are
known in the art
and could be used in embodiments of the present invention.
The air cart 110 comprises sensing equipment, including a ground speed sensor
40
for detection of the ground speed of the air cart 110. Thus, variations in the
ground speed
of the air cart 110 may be taken into account when calculating the application
rate, so that
seeds can be dispensed evenly.
With respect to this embodiment, the 'bypass mode of operation' is selected
through
the primer input unit 60, which primes the air distribution system 125 of an
air seeder,
engaging the variable rate drive mechanism to rotate the metering wheel 121 at
a
predetermined rate. The primer input unit 60 is commonly operated in a
situation when the
ground speed of the air seeder is below a minimum predetermined ground speed.
For
example, suppose a farmer is at the beginning of the seeding process, with the
tractor
stationary in the field. The primer input unit 60 allows the farmer to deposit
seeds during
the period of time prior to the tractor reaching a predetermined minimum
ground speed.
Once the tractor attains the predetermined minimum ground speed, the variable
rate drive
mechanism rotates the metering wheel automatically at a rate determined by the
ground
speed. In order to accomplish this, the farmer presses one or several primer
input buttons
CA 02286490 1999-10-29
in the cabin of the tractor. Thus, the farmer bypasses the seed dispensing
process, selecting
one of several available predetermined rates at which the variable rate drive
mechanism
rotates the metering wheel. Once the tractor reaches the predetermined minimum
ground
speed, the seeder may enter the 'regular mode of operation' in which the
variable rate drive
mechanism rotates the metering wheel at a rate consistent with the ground
speed, or it may
continue to run in the 'bypass mode of operation' at the selected
predetermined rate,
according to operator input through the primer input unit 60. The problem of
having field
areas left unseeded, due to the inability of the variable rate drive mechanism
to automatically
rotate the wheel, when the seeder travels at a speed below a predetermined
minimum ground
speed, is thus solved in a time efficient manner.
Figure 6 is a block diagram of a system in accordance with the present
invention as
it applies to seeders and planters. The microcontroller 30 receives signal
from the ground
speed detector 40 and the user interface 60. A feedback loop returns to the
microcontroller
30 the rotation rate of the metering wheel 121 at any moment. Based on this
information,
the microcontroller 30 calculates the desired rate at any moment and commands
the metering
wheel 121 to rotate at the desired rate. As previously indicated, the user
interface 50
comprises operator setting buttons 55 and priming buttons 60.
Figure 7 is flow chart showing the microcontroller 30 function as it applies
to air
seeders and planters, in one embodiment of the invention. At step 31, the
microcontroller
30 determines whether the ground speed is greater than a predetermined minimum
speed.
If the ground speed is greater than the minimum speed, the driving mechanism
20 operates
in its regular mode of operation 33, thus having a controlled rate 70 based on
the detected
ground speed. If the ground speed is zero, i.e., the cart is stationary, the
microcontroller 30
allows the driving mechanism to operate in the bypass mode if the bypass mode
is selected
by an operator, by pressing prime buttons 35. After engaging the driving
mechanism in the
bypass mode, the operator waits for a predetermined length of time 37 during
which the
product is dispensed from the tank at a predetermined rate, into the air
stream and carried
through the distribution lines to the ground openers. After the predetermined
length of time
elapses, the tractor can begin travelling in the field and product is ready to
be seeded.
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Afterwards, once the tractor starts travelling, product is seeded based on the
predetermined
rate selected by the operator from the user interface, at which the driving
mechanism runs
in the bypass mode.
In the bypass mode, the availability of product for seeding depends on the
predetermined length of time during which product was metered from the tank
into the
distribution lines. Therefore, optimally, the predetermined length of time
that the operator
has to wait and the predetermined rate at which the driving mechanism runs in
the bypass
mode are related to each other. These quantities can be determined based on
experience or
can be calculated by taking into account factors such as: the amount of
product necessary
to fill the distribution lines, an average distance that the cart has to
travel in order to reach
the minimum ground speed, and the time for the metering mechanism to start
operating in
its regular mode.
According to the embodiment presented in Figure 7, the driving mechanism 20
may
operate in the bypass mode only when the ground speed is below the minimum
speed. The
driving mechanism 20 enters the regular mode 33 once the minimum ground speed
is
detected. However, it has to be understood that in other embodiments, the
bypass mode can
be selected any time by the operator, regardless of the ground speed.
For example, the driving mechanism can operate in the 'bypass mode' for a
predetermined
period of time measured from the moment when one or more primer buttons on the
primer
input unit 60 are activated, or for as long one or more primer buttons are
pressed. It will be
appreciated by a person skilled in the art that the selection of the 'bypass
mode of operation'
through activation means such as switches, levers or buttons on the primer
input unit 60, can
be achieved in numerous ways.
In one embodiment of the invention, the priming feature on an air cart works
as
follows: An AIR CART key and a MODE key are pressed at the same time on the
user
interface. A 10-second prime begins with the meters being turned at about
15 rotations/minute (rpm) provided that a meter switch is on and a master
switch is on and
hydraulic pressure is applied. The 10-second prime can be interrupted if
ground speed is
sensed or the master switch is turned off. As a person skilled in the art will
easily recognize,
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CA 02286490 1999-10-29
the exact numerical values presented here are used only as an example, but any
suitable other
values can be used.
Planters
Like the air seeders, planters have several tanks for holding seed or
fertilizer, and an
air distribution system comprising a series of hoses. Product travels through
the hoses,
entering through a series of inlets into several chambers for storing the
product. In one
embodiment, each chamber has joined to it a fingered singulator disk. Each
chamber is
located just above a corresponding ground opener. The singulator disk rotates
such that as
each finger passes the place where product puddles into the chamber, a single
seed/fertilizer
falls into the finger. The disk continues to rotate such that each subsequent
finger can pick
up product. The filled fingers pass a brush that eliminates the chance of
multiple seeds being
in a single finger. The filled fingers pass another opening in the disk when
the product is
dropped onto an elevator opening that carries the product to the ground
opener.
The driving mechanism 20 of the planters can operate in a regular mode and a
bypass
mode, as previously discussed. Figures 6 and 7 apply to planters, as well as,
seeders.
In the regular mode, the driving mechanism 20 of the planter is activated into
rotating
the singulator disk at the controlled rate output 70. In this mode, the
controlled rate output
70 is a function of the operator settings and of the detected ground speed.
With respect to seeders, in the embodiment depicted in Figures 6 and 7, the
operation
in the regular mode is conditioned by the planter achieving a minimum ground
speed.
In the bypass mode of operation, the operator can prime the singulator disk to
rotate
at a predetermined rate, regardless of the detected ground speed. The
singulator disk is
activated through a primer button on the user interface, in the cab of the
vehicle towing the
planter. On pushing the primer button, a bypass signal is sent to the
controller to start
rotating the disk at the predetermined rate. After engaging the bypass mode,
the operator
waits for a predetermined length of time during which product is singulated
into the fingered
disk and dropped into the elevator.
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The bypass mode can be selected by the operator in any circumstance. A
situation
in which the use of the bypass mode is desirable is at the beginning of the
planting process.
In this case, while stationary, the operator engages the primer mechanism by
pressing the
primer button, then waits for a predetermined length of time during which the
primer
mechanism runs and product is being singulated into the fingered disk at a
predetermined
rate, and dropped into the elevator. When the planter begins travelling in the
field, seed is
ready to be planted through the ground openers.
In one embodiment of the invention, the priming feature on a planter works as
follows: a PRIME switch is held on the switch box. The meters are turned at
15 rotations/minute (rpm) as long as the PRIME switch is held. As a person
skilled in the art
will easily recognize, the exact numerical value presented here is used only
as an example,
but any suitable other values can be used.
Sprayers
Referring now to Figure 8, a basic sprayer is depicted. Generally, a sprayer
has at
least one storage tank 15 for chemicals. In an embodiment of the invention,
the tanks 15
contain a pre-mixed chemical ready for distribution. In an alternative
embodiment, the tanks
15 store only water and, as the water travels through the distribution lines
25, the water is
injected with the correct amount of chemical.
Referring also to Figure 9, The required gallons/acre ratio is known and
programmed
into a microcontroller 30, connected to the user interface 50 in the cab of
the tractor towing
the sprayer. The gallons/acre ratio is dependent upon the type of crop, the
type of chemical,
the position in the field, and the like. A pump 22 pushes the product into the
distribution
lines 25. As product is pushed into the distribution lines 25, it travels down
at the flow rate
necessary to dispense the required gallons/acre out of the nozzle on the spray
bar. During
this process, the entire system automatically remains pressurized at the
appropriate level.
The flow rate is dependent upon the ground speed of the sprayer.
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The pump can be a centrifugal pump, in which fluid is fed into the center of a
rotating
pump impeller and is flung out to the impeller rim with considerable
"centrifugal force" or
pressure. The pressure is determined by the speed the pump impeller is
turning, which is
directly connected to a hydraulic motor shaft.
During a regular mode of operation, an autorate system ensures that the
correct
gallons/acre ratio is dispensed from nozzles, regardless of variations in the
ground speed of
the sprayer. Various autorate systems are available in the art, that are
suitable for use with
the present invention. In general, the autorate systems adjust the flow rate
in the distribution
lines 25, by adjusting the pressure level in the system. As depicted in Figure
9, the actual
flow rate is computed by the microcontroller 30 based on signals from the
ground speed
sensor 40, the user interface 50, a flow meter 42 and a pressure sensor 44.
The flow meter
42 and the pressure sensor 44 are connected in a feedback loop with the
microcontroller 30,
informing the microcontroller 3 0 of the flow rate and of the pressure in the
distribution lines,
respectively, at any given moment.
A minimum ground speed is required, in order for the autorate system to work.
Furthermore, the autorate system works only within a range of travel speeds
which is limited
by the nozzles. In an embodiment of the invention, when the speed falls out of
this range,
an alarm will sound to inform the operator.
In desired circumstances, the system can operate in a bypass mode. In this
mode, a
primer mechanism is selectively operated, and a predetermined flow rate,
independent on the
ground speed, is selected through the primer unit 60 on the user interface 50.
In the bypass mode, the primer feature pressurizes the distribution lines 25
of the
sprayer at a predetermined pressure level, related to the predetermined flow
rate that is
selected. The predetermined pressure level is achieved by controlling a valve
80 in the
distribution lines. The pressurized system starts the pump 22 and product
travels at the
desired flow rate. In an embodiment of the invention, the prime feature is
engaged by
holding a button on the primer unit 60, and is disengaged when the button is
released. In an
alternative embodiment, the operator could only activate the primer feature by
pushing a
button on the primer unit 60, and the mechanism would run by itself,
controlled by a
CA 02286490 1999-10-29
controller unit, for a predetermined length of time. In one embodiment of the
invention, the
priming feature on a sprayer works as follows: the operator can enter a prime
set point in psi
or kPascals; when a PRIME switch is held, the pressure is controlled to the
operator set
point; when the PRIME switch is released, control goes back to the normal
controller.
Figure 10 presents the microcontroller function in accordance with an
embodiment
of the invention, as it pertains to sprayers. The following features, as they
relate to the
invention and to Figure 10, are defined:
Booms ON or OFF: The priming feature only works on boom sections of the
sprayer, that have a corresponding switch turned on. Boom sections can be
turned on or off
at the operator's choice.
Flow Calibration Mode: This mode is entered by the operator, through the user
interface.
Controlled Pressure Setpoint: The priming feature in this case controls the
pressure
in the system. The pressure setpoint indicates the pressure to which the
controller will adjust
the system. This value is entered at the user interface.
Controlled Rate Setpoint: In the regular operating mode, the sprayer applies a
product at a given rate. The rate set point is the operator entered rate to
which the controller
will control the system.
Relating to Figure 10, the sprayer has two controllers: a rate controller and
a pressure
controller. Depending on the mode chosen and switch settings (prime feature on
or off), the
sprayer will either control the system at a set pressure point or set rate
point.
Referring now to all Figures 3-10, embodiments of the invention where
described in
detail for the case where a bypass mode was activated directly by an operator,
via the
primer unit 60 on the user interface 50. As previously mentioned in connection
with Figure
3, the bypass mode could also be activated when the microcontroller 30
receives bypass
signals from other sensors 42, denoted herein as bypass sensors 42. The bypass
sensors 42
may detect values of bypass parameter. When the bypass parameters attain
certain values,
the bypass system may be automatically triggered, without direct user
intervention. One
aspect of the invention contemplates the activation of the bypass mode based
the
16
CA 02286490 1999-10-29
microcontroller receiving a bypass signal from a sensor determining a
predetermined height
of an implement of an agricultural product distribution machine, relative to
the ground. Such
an embodiment may operate as follows: the user, when in the field, commands
the lowering
of the implement from a transport position to a working position as per normal
operation.
The implement can be a tillage implement for air seeders, or a spray boom for
a sprayers or
a toolbar for planters. During lowering, when the implement reaches the
predetermined
height relative to the ground, the sensor sends a bypass signal to the
microcontroller 30,
leading to the activation of the driving mechanism in the bypass mode. The
predetermined
height is preferably calculated in advance such that by the time the implement
is in full
working position, the machine is fully primed and ready to begin working.
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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