Planting – Drilling – Having depositor feature
Reexamination Certificate
2002-09-17
2003-07-01
Novosad, Christopher J. (Department: 3671)
Planting
Drilling
Having depositor feature
C111S177000, C111S200000, C111S904000, C701S050000, C340S674000, C340S684000, C406S026000
Reexamination Certificate
active
06584920
ABSTRACT:
This invention is in the field of air seeders and in particular addresses control of the air flow in the air streams in such seeders.
BACKGROUND OF THE INVENTION
In an air seeder, agricultural materials such as seed, fertilizer, and chemicals are dispensed from respective holding tanks into an air stream that carries the materials through a distribution network, typically a series of tubes and manifolds, to an array of seeding tools mounted along the width of an implement.
The rate of material being applied can vary greatly depending on the crop requirements. An air seeder may be required to apply as low as four or five lb/acre when seeding canola with no fertilizer, and up to 300 lb/acre or more when seeding wheat at high fertilizer rates. Where an air seeder is seeding 40 acres/hour, the air stream must carry about 3 lb/minute of material at the low rate and about 200 lb/minute at the higher rate. Much more air is required at the higher rate to carry the increased amount of material through the system.
It is preferred to have just enough air to carry the material to the furrow openers and maintain uniform distribution across the implement. Where excess air is present, the agricultural materials are traveling at higher speed than necessary when they exit the tube at the furrow opener. The faster the material is traveling when it exits the tube, the more it tends to bounce out of the furrow. Excess speed also can crack and damage seed. On the other hand, where insufficient air flow is present, the distribution across the implement can vary to an unsatisfactory degree. With insufficient air flow, the material being carried will begin to pulsate, and then material will begin to drop out of the air flow and gather at a spot in the distribution network and cause a blockage. Preferably the air flow is maintained at an appropriate level between insufficient and excessive.
Air seeders commonly have two or more tanks mounted on a cart, each tank carrying a particular agricultural material such as seed, fertilizer, chemical or the like. In a “single shoot” system, these materials are all metered into a single air stream and carried through a single distribution network such that a blend containing all the materials is deposited in a single furrow. In a “double shoot” system, two distinct and separate air streams and distribution networks are present. One or more materials are metered into each air stream and carried through a corresponding distribution network to be deposited in two separate furrows. Similarly “triple shoot” systems are also available providing three distinct and separate air streams and corresponding distribution networks, and increasing multiple systems are foreseeable.
The distinct air streams are typically provided in various ways. A single fan system includes dampers to divide and control the flow of air from the fan into separate air streams each flowing through a corresponding separate distribution network. This type of system is disclosed in U.S. Pat. Nos. 6,296,425 and 6,192,813 to Memory et al., and in 5,996,516 to Benneweis et al. In such a system the total volume of air is varied by varying the fan speed, and the proportion of the total volume directed to each separate air stream is controlled by the dampers. Where the fan speed is held constant, adjusting a damper to direct more air to one air stream will necessarily reduce the volume and speed of the other air streams. In the disclosed systems, a number of sensors monitor the speed of particles carried in the air stream, and the air flow in each air stream is automatically controlled by damper and fan speed adjustments that are made in response to particle speed variations.
Alternatively, a plurality of fans can each provide a separate air stream to each distribution network. The air flow in each air stream is then individually controlled by adjusting each fan speed, and the problem of cross-variation between air flows in separate streams is avoided. Alternatively again in a triple shoot system, a combination system can be provided where one of two fans provides air flow to one air stream, and the other of the two fans provides air flow to two other separate air streams, controlled by dampers.
In conventional seeding systems where the travel speed is substantially constant and where application rates remain constant, the amount of material per minute carried by each air stream, or the material flow rate, remains substantially constant. In such systems the air flow in each air stream can be conventionally adjusted with either manual or remotely controlled damper and fan speed adjusting mechanisms to an appropriate level, such that the air flow is not excessive and yet blockages are avoided. The required air flow also varies with humidity, temperature, and similar atmospheric conditions, as well as altitude. As well sharp slopes in a field can require a higher air flow than is required on flat fields. The material must be pushed uphill from the tank to certain portions of the implement as it moves through the field. Air flow requirements thus increase and decrease as these conditions vary, however the conventional adjustments have allowed for satisfactory operation in conventional fixed rate seeding operations.
Typically the metering devices are driven by a ground drive mechanism so that the amount of material per minute that is dispensed varies directly with ground speed so that the application rate is constant as speed varies. Typically the normal operating ground speed is the maximum speed that will be encountered and when the implement slows for corners and the like, the dispensing rate is reduced, and the air flow is somewhat excessive until normal operating ground speed is again achieved. Thus a conventional air seeder with a constant air flow set as required to carry the material dispensed at a normal ground speed will not experience blockages, since at times the air flow will be excessive, but at no time will the air flow be insufficient.
In practice it is not uncommon when application rates are increased or other conditions change for blockages to occur. The operator then clears the blocked runs manually and increases the air flow to avoid a recurrence. It is also not uncommon for the operator to maintain the higher air flow rate when conditions change again such that a reduced air flow is warranted. It is human nature to avoid blockages which must be manually cleared, and instead opt for excessive air flow which has no immediate consequences for the operator. Higher than necessary air flows are thus common in conventional air seeders.
Recent trends toward variable rate seeding have made air flow adjustment more problematic. In variable rate seeding, the application rate of each agricultural material can be varied by manual or automatic controls that vary the rate of material being dispensed by the metering devices as the machine travels along the field.
In a typical air seeder, the system is calibrated such that for each revolution of a metering device, typically a fluted roller or auger, a known quantity of the metered agricultural material is dispensed into an air stream for distribution across the width of the air seeder. Densities of agricultural materials vary considerably, and such calibration is necessary in order to determine the actual weight of the particular material that is being dispensed per revolution of the metering device.
In conventional seeding, this rotational speed varies only with the ground speed—the operator adjusts the ground drive mechanism to set the ratio between the rotational speed of the metering device and the rotational speed of the wheel on the ground such that the desired application rate results. For every turn of the ground wheel, the seeder will pass over a known area, and the metering device will rotate the required number of times to dispense the amount of agricultural material that is desired to be applied on that area. The desired application rate is thus applied to the field.
In variable rate seeding, this ratio between the rotational speed of the meteri
Bourgault Industries Ltd.
Frost Brown Todd LLC
Novosad Christopher J.
LandOfFree
System and method for adjusting air flow in air seeding... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with System and method for adjusting air flow in air seeding..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and System and method for adjusting air flow in air seeding... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3016366