CALIBRATION PROCEDURE FOR
BROADCAST APPLICATION
Matthew D. Schuster and Steve
Salisbury
Calibrating a sprayer for a band application is a fairly simple process. In fact, it is really no different than calibrating for a broadcast application. To begin calibrating your sprayer you must collect three pieces of information:
1. Speed (mph)
2. Sprayer output (GPA)
3. Tank capacity (gallons per tank)
From that you can use that information to calculate:
1. Acres treated per tank
2. Product added per tank
PROCEDURE:
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1. Speed: |
0.682 |
x |
feet |
= mph |
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seconds |
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0.682 is a constant.
It saves you the trouble of converting seconds to hours, feet to miles,
etc.
feet measured distance for your test drive
seconds time it takes for you to travel the measure
distance (be sure to use a stop watch, dont rely on the speedometer)
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2. Output: |
5940 |
x |
gallon/minute/nozzle |
= GPA |
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nozzle spacing (inches) |
mph |
5940 is a constant.
It saves you the trouble of converting inches to miles, miles to acres,
minutes to hours, etc.
gallon/minute/nozzle measured amount of fluid
being sprayed out of one nozzle.
Typically you want to check all nozzles to ensure that the output is
consistent. If they are then average
the nozzles together.
Nozzle spacing actual inches between the nozzles on the
sprayer boom.
mph speed that was determined in step 1.
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3. Tank
capacity: |
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gallons per tank |
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4. Acres treated
per tank: |
gallons per tank |
= acres per tank |
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GPA |
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gallons
per tank
from step 3.
GPA from step 2.
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5. Product
added per tank: |
acres/tank |
x |
product/acre |
= product per tank |
acres
per tank
from step 4.
product
per acre
amount of product recommended on the pesticide label for a broadcast
application.
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EXAMPLE:
Your four-wheeler is equipped with a 100-gallon tank. The boom has three nozzles spaced 20 inches apart and delivers an average 0.30 gallons per minute. In a speed test the sprayer traveled 100 feet in 13.7 seconds. You want to spray Roundup Ultra at 1 pint per acre to your borders to control kochia. You have 10 acres to treat.
How many acres can you treat with one tank?
How many times will you have to refill?
And how many pints of Roundup Ultra will you have to add to the tank at each fill up?
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1 mph: |
0.681 x 100 ft |
= 5 mph |
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13.7 seconds |
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2. GPA: |
5940 x 0.30 GPM |
= 17.82 GPA |
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20 inches x 5 mph |
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3. Tank Capacity: |
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= 100 gallons |
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4. Acres/tank: |
100 gallons/tank |
= 5.6 acres/tank |
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17.82 GPA |
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5. Product/tank: |
5.6 A/tank x 1 pint/A |
= 5.6 pints/tank |
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How many times to fill up? |
= 2 (10 acres χ 5.6 A/ tank) |
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How many pints of Roundup at each filling? |
1st time: 5.6 pints |
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2nd time: 4.4 pints |
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10 acres total 5.6 acres treated |
= 4.4 acres left |
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4.4 acres Έ 5.6 acres/tank |
= 0.785 (or 78.5%) |
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100 gallons x 0.785 |
= 78.5 gallons |
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5.6 pints/tank x 0.785 |
= 4.4 pints |
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ADJUSTING:
The calibration problems above are for a sprayer that hasnt been adjusted. Say for instance you want to apply 20 gallons per acre. Your sprayer will be traveling at 5 mph and the boom is 30 feet long with nozzles 20 inches apart. How would you adjust the sprayer to deliver that output?
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Gallons per minute: |
GPA x mph x nozzle spacing or band width (in) |
= gpm |
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5940 |
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To achieve that gpm you can either adjust the nozzle size, pressure, or speed. With the senario above, the gpm of the sprayer would be 0.34 gpm. If your currently using teejet XR8003VS nozzles the sprayer would have to be pressurized at 50 psi to deliver that gpm. This would result in too much drift.
The best thing to do is switch to a XR8004VS. At 30 psi the gpm would be around 0.35. A XR8005VS nozzle would deliver 0.34 gpm between 15 and 20 psi. By changing the nozzles then the pressure and speed would only have to be altered slightly to achieve 20 gpa.
