OPERATORS HANDBOOK 8
CALIBRATION PROCEDURES
The following steps set out a method of sprayer calibration:
Read the label on the Container for the Application rate & recommended spray nozzle type.
To apply a specified rate of chemical to the target surface, you need to know the total sprayer
output, the travel speed and the swath width. Then calculate the application rate.
Measure Total sprayer output [L/min]
Set the pressure at the correct level for spraying determined by the type of nozzles.
All nozzles used for spraying should be left on. For initial trials set pressure at ~ 2 bar
and adjust as needed.
1. Fill the spray tank with clean water. Run the sprayer at the correct pressure with all nozzles operating.
2. Place a measuring jug under first nozzle for one minute. Measure how much water is in the jug.
3. Repeat for all nozzles. Nozzle output should not vary by more than 10%. If it does, the nozzle could
be worn or damaged and should be replaced. All nozzles on the boom should have a similar output.
4. Add all the jug measurements to find the total sprayer output in litres per minute.
Measure the travel speed [km/h]
The normal speed for spraying with small boom sprayers is 4–10 km/h. The slower you travel
the higher the application rate. Adjust travel speed to suit ground conditions.
1. Measure how many seconds it takes to travel 100 metres with the sprayer attached and half full.
2. Calculate your travel speed by inserting the time in seconds into the following formula:
Travel speed (km/h) =distance travelled in meters (say 100m) x3.6 / Time taken (in seconds)
Calculate spray application rate [L/Ha]
First, measure your swath width (in metres). For general broadcast spraying, the swath width is equal
to the number of nozzles multiplied by the nozzle spacing. For band spraying the swath width is
equal to the total of all the band widths. Calculate the application rate using the following formula :-
Application rate (L/ha) = 600 x total sprayer output (L/min)
swath width (m) x travel speed (km/h)
Example: If total sprayer output is 5 L/min, speed is 8 km/h, and swath width is 6m,
Application rate = 600 x 5 = 62.5 L/ha
6 x 8
If the application rate is less than specified, increase the pressure and repeat calibration to
achieve correct rate.
Nozzle Fitted
Type (Drop Size
Application Rate
Spray Pressure
www.tti.com.au
Call 1800 816 277
