Note: Descriptions are shown in the official language in which they were submitted.
CA 02252321 1998-10-30
PRIMER SYSTEM FOR PRODUCT DISTRIBUTION MACHINES
FIELD OF INVENTION
S The present invention relates to a primer system for product distribution
machines, such as an agricultural air seeder, a precision planter, a sprayer,
or the like.
BACKGROUND OF THE INVENTION
Agricultural machines used for applying product over a field (referred to
herein
as product distribution machines), such as seeders, fertilizers, planters,
sprayers, and the
like, must apply the product evenly across the entire field.
In the past, the practice of averaging product requirements for an entire
field was
common. However, averaging product requirements resulted in over fertilizing
some
areas and under fertilizing others. Now, it is necessary for each area of the
field to
accurately receive a required amount of fertilizer. Technological advances now
enable
farmers to obtain higher accuracy in product application. For example, when
attached
to a combine, yield monitors measure the amount of grain being harvested as it
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 farming method. Variable
rate systems
technology means farmers can then apply fertilizer, herbicides and seed at the
rate needed
for a particular soil site.
Variable rate systems were designed to allow the operators of 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
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CA 02252321 1998-10-30
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 equipment
are known.
A typical agricultural spreader 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 product
distribution
machine. As the 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/hour is chosen with some known seeders. If the
seeder
is stationary, but the wind is blowing the grass or the straw around the
sensor, the sensor
does not begin dispensing seed upon detecting the speed of the grass or of the
straw. If
a stationary seeder is accelerated to an operating speed, it will 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 about 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 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 seed 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
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CA 02252321 1998-10-30
is wasteful of space and money. It is advantageous for farmers, especially row
crop
farmers, to use all available land. Accurately dispensed seeds achieves better
yields.
In some circumstances, agricultural product distribution machines must be
backed
into a corner of a field before they can be moved forward and the seeding
process begins.
This is a situation where 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
It is an object of the present invention to provide an improved primer system
for
product distribution machines.
The invention relates to an apparatus for distributing agricultural product
over a
ground surface. The apparatus may, for example, be an air seeder, a precision
planter,
a sprayer, or the like. The apparatus includes a storage means for storing a
quantity of
product to be distributed. The apparatus also includes conveying means for
conveying
product from the storage means to the ground surface. The apparatus also
includes
control means for controlling the rate of transfer of the product from the
storage means
to the conveying means. The control means includes a speed sensor for
detecting the
ground speed of the machine. The control means also includes an automatic
dispenser
for automatically transferring product from the storage means to the conveying
means at
a rate proportional to the ground speed of the machine upon the attainment of
a
pre-determined minimum ground speed. The control means also includes a
manually
operable dispenser for transferring product from the storage means to the
conveying
means prior to the attainment of the minimum ground speed. In an embodiment of
the
invention, the manually operable dispenser includes means for controlling the
rate of
transfer of the product from the storage means to the conveying means. In an
embodiment of the invention, the manually operable dispenser is operable from
a remote
location, such as from the a tractor that is pulling a trailer with the
apparatus for
distributing agricultural product.
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CA 02252321 1998-10-30
According to the invention there is provided an apparatus for distributing
agricultural product over a ground surface, the apparatus comprising: storage
means for
storing a quantity of product to be distributed; conveying means for conveying
product
from the storage means to the ground surface; and control means for
controlling the rate
of transfer of the product from the storage means to the conveying means, the
control
means comprising: a speed sensor for detecting the ground speed of the
machine; an
automatic dispenser for automatically transferring product from the storage
means to the
conveying means at a rate proportional to the ground speed of the machine upon
the
attainment of a pre-determined minimum ground speed; and a manually operable
dispenser for transferring product from the storage means to the conveying
means prior
to the attainment of the minimum ground speed.
In one aspect of the invention there is provided an apparatus that allows both
the
automatic and selective operation of a variable rate system of an agricultural
product
distribution machine, from a remote location such as the cab of the tractor,
regardless of
the detected ground speed.
In a further aspect of the invention, a primer system for product distribution
machines, such as an agricultural air seeder, a precision planter, a sprayer,
or the like
included 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 the tank into the distribution system at a certain
rate. The
driving mechanism can run automatically or it can be selectively operated,
based on
commands received from a controller. The controller may receive signals from a
user
interface and from sensing equipment, such as a ground speed detector, a
pressure sensor,
a flow meter etc. 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
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 controller to run the driving
mechanism at a
predetermined dispensing rate, of the detected ground speed.
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CA 02252321 1998-10-30
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
Figure 1 is a block diagram of a primer system.
Figure 2 is a block diagram of a primer system in accordance with the present
invention.
Figure 3 represents a basic air delivery system
Figure 4 represents the metering mechanism of the air delivery system in
Figure 3.
Figure 5 is a block diagram of a primer system in accordance with one
embodiment of the present invention, as it applies to seeders and planters.
Figure 6 is a flow chart showing the controller function, as it applies to
seeders
and planters, in one embodiment of the invention.
Figure 7 represents a basic sprayer system.
Figure 8 is a block diagram of a primer system in accordance with the present
invention, as it applies to sprayers.
Figure 9 is a flow chart showing the controller function, as it applies to
sprayers,
in one embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
Referring to the Figure 1, a primer system for a product distribution machine
10
includes at least one tank 15 for holding product and a distribution system
25. Product
is passed from the tank 15 into the distribution system 25 by a driving
mechanism 20, at
a rate related to the desired rate of product distribution of the product
distribution
machine 10. The product distribution machine 10 includes a controller 30,
which enables
driving mechanism 20 to run automatically or to be selectively operated by an
operator.
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CA 02252321 1998-10-30
The illustrated product distribution machine 10 is an agricultural spreader,
towed
by a vehicle (not shown) in a field onto which product has to be applied. The
controller
30 receives command signals from a ground speed sensor 40 and from a user
interface
50.
The ground speed sensor 40 detects the ground speed or forward speed of the
system for product distribution machine 10, as the vehicle tows the product
distribution
machine 10, in the field.
The user interface 50 allows the operator to monitor and set various
parameters
relating to the process, such as application rate, product size, moisture
content, density,
location in the field implement widths, calibration numbers, and the like. The
process
parameters can be changed through operator settings buttons 55.
A primer unit 60 comprising one or more buttons, on the user interface 50,
allows
the operator to selectively operate the driving mechanism 20, as it will be
further
described.
1 S The buttons on the user interface 50 may, alternatively, be any input
means, such
as keys on a keypad, switches, lever, and 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
distribution
system travels in the field. In a preferred embodiment, the user interface 50
comprises
a screen and a console unit, situated in the cab of the vehicle towing the
product
distribution machine 10.
In the block diagram of Figure 2, the ground speed and the data from the user
interface are collectively referred to as rate data input 65. The rate data
input 65 is
processed by the controller 30. Upon processing, the controller 30 activates
the driving
mechanism 20 which, as a result, 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, that 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 and on the
operator
settings. Therefore the controlled rate output 70 varies with the rate data
input 65 to
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CA 02252321 1998-10-30
compensate for ground speed fluctuations and produce a consistent application
of the
product onto the field.
Generally, the driving system 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. The value of the
minimum
speed can vary from 0 miles/hour up.
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
selection of the bypass mode of operation by the operator is done through the
primer unit
60. By pressing a button on the primer unit 60, the operator initiates a
program that
bypasses the input from the ground sensor 40 to the driving mechanism 20. In
other
words, by pressing a primer button on the user interface 50, a bypass signal
is sent to the
controller 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 depends on the
detection of a minimum ground speed, one usually engages the driving mechanism
20
in the bypass mode by using the primer unit 60, 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 corners, when crossing waterways.
In a preferred embodiment, the operator may select from a plurality of
predetermined rates at which the controller 30 can run the driving system Z0,
various
rates being suited for various situations. Each rate may have a corresponding
primer
button on the primer 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
agriculture machines.
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CA 02252321 1998-10-30
Air seeders
As depicted in Figures 3 and 4, a basic air delivery system consists of an air
cart
10, an air distribution system 25 and a seeding tool 27. The seeding tool 27
may be a
series of ground openers. The air distribution system 25 comprises a series of
hoses or
a manifold. The air cart 10 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 10 includes one or more
tanks 15 to
hold products like seed and fertilizer, a metering system 20 to deliver the
appropriate
amount of product into the distribution system 25 and a hydraulic fan (not
shown) that
supplies air to the system.
The metering system 20 controls the dispensing rate of product from the tanks
15
into the distribution system 25. In turn, the dispensing rate of the metering
system
determines the application rate of product on the field.
Referring now to Figure 4, the metering system 20 includes a metering wheel,
specifically designed to dispense a predetermined amount of product in
specific time
intervals. As product falls through the metering system 20, it is carned by
airflow
through the manifold 25 to the headers (not shown), where the product is split
into
several runs and falls down through the ground opener and into the furrow
created by the
opener.
The metering system 20 is driven automatically by a variable rate (VR) drive
mechanism. In the case of a metering wheel, the VR mechanism will rotate this
wheel at
various rates. Many designs of variable rate drive mechanisms are known in the
art and
any of them could be used in conjunction with the present invention.
The seed cart 10 comprises sensing equipment, including means for detection of
the ground speed of the cart. The ground speed sensor or detector 40 allows
one to take
into account variations in the ground speed of the implement when calculating
the
application rate, such that seeds can be dispensed consistently.
With respect to this embodiment, the primer unit 60 primes the air
distribution
system 25 of an air seeder, engaging the VR to rotate the metering wheel 20 at
a
predetermined rate.
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CA 02252321 1998-10-30
Figure 5 is a block diagram of a system in accordance with the present
invention
as it applies to seeders and planters. The controller 30 receives signal from
the ground
speed detector 40 and the user interface 60. A feedback loop returns to the
controller 30
the rotation rate of the metering wheel 20 at any moment. Based on this
information, the
controller 30 commands the metering wheel 20 to rotate at the necessary rate.
As
previously indicated, the user interface 50 comprises operator setting buttons
55 and
priming buttons 60.
Figure 6 is flow chart showing the controller function as it applies to air
seeders
and planters, in one embodiment of the invention. At step 31, the controller
30
determines whether the ground speed is greater than zero i.e. whether the cart
is non-
stationary. If the ground speed is greater than zero, 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
controller 30
allows the driving mechanism to operate in the bypass mode if the bypass mode
is
selected by an operator, by pressing the prime button 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 metered 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.
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, the time for the metering mechanism to start operating
in its
regular mode.
According to the embodiment presented in Figure 6, the driving mechanism 20
operates 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
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CA 02252321 1998-10-30
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.
In one embodiment of the invention, the priming feature on an air cart works
as
follows: An AIR CART and MODE keys 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.
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.
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 forgers 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 5 and 6 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 a 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 5 and 6, the
operation in the regular mode is conditioned by the planter achieving a
minimum ground
speed.
CA 02252321 1998-10-30
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.
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.
Sprayers
Referring now to Figure 7, a sprayer is depicted. 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.
The required gallons/acre ratio is known and programmed into a controller 30,
connected to a 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.
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CA 02252321 1998-10-30
During this process, the entire system remains pressurized at the appropriate
level. The
flow rate is dependent upon the ground speed of the sprayer.
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
S 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
8, the actual flow rate is computed by the controller 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
controller 30, informing the controller of the flow rate and of the pressure
in the
distribution lines, respectively, at any given moment.
As in the case of seeders, 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
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CA 02252321 1998-10-30
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 9 presents the controller 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 9, 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.
Cameras Installed: Cameras that detect plant material are installed on the
spraying
bar of the sprayer. Upon detecting plants to be sprayed, they send signals to
a controller,
to release spray onto the detected plants.
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 9, the sprayer has two controllers: a rate controller and a
pressure controller. Depending on the mode chosen, the detecting equipment
(cameras),
and switch settings (prime feature on or off), the sprayer will either control
the system
at a set pressure or set rate.
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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