WHEN TO SPRAY:
Results will be best when wind speed is low, temperature low and relative humidity high. An ideal
time is at sun-up when these conditions are most likely to apply.
APPLICATION RATE:
The application rate can be determined using the following formula:
•
Speed of travel
–
increasing speed reduces application rate and vice versa
•
Operating pressure
–
increasing pressure increases the application rate and reducing pressure
decreases the rate
•
Nozzle size
–
increasing the nozzle size increases the application rate
Application Rate (L/Ha) =
600 × 𝑁𝑜𝑧𝑧𝑙𝑒 𝑂𝑢𝑡𝑝𝑢𝑡 (𝑙 𝑚𝑖𝑛
⁄
)
𝑆𝑝𝑒𝑒𝑑 (𝑘𝑚 ℎ𝑟
⁄
)×𝑁𝑜𝑧𝑧𝑙𝑒 𝑆𝑝𝑎𝑐𝑖𝑛𝑔 (𝑚)
SPEED:
The speedometer on many vehicles may not be sufficiently accurate at the slow speeds used when
spraying. If in doubt it should be checked by the following method.
Measure and mark a distance of 100 metres. Approach the starting mark at the required spraying
speed and accurately measure the time in seconds to reach the finishing mark. The ground speed can
then be calculated as follows.
Speed (km/hr) =
360
𝑡𝑖𝑚𝑒 𝑖𝑛 𝑠𝑒𝑐𝑜𝑛𝑑𝑠 𝑓𝑜𝑟 100 𝑚𝑒𝑡𝑟𝑒𝑠
As the output to the boom cannot be regulated on standard units, the application rate can only be
varied by changing the operating speed. The slower you drive, the higher the application rate.
NOZZLE OUTPUT:
1.
Partly fill the sprayer tank with water and mark the level or refer to the sight gauge
2.
Run the sprayer for several minutes
with all boom’s sections operating and measure the time
carefully
3.
Refill the sprayer tank to the mark using a measuring jug and record the amount added
4.
The average output for nozzle in litres per minute can be calculated as follows
Nozzle Output (l/min)
=
𝐿𝑖𝑡𝑟𝑒𝑠 𝑈𝑠𝑒𝑑
𝑁𝑜.𝑁𝑜𝑧𝑧𝑙𝑒𝑠 ×𝑁𝑜.𝑀𝑖𝑛𝑢𝑡𝑒𝑠
The output calculated should agree with the flow rate shown in the Spray Nozzle Selection Chart, for
the particular nozzles fitted.
5.
If the nozzle output is lower than shown in the table the pressure may be increased and the test
repeated or, if more than shown, the pressure may be reduced. (if optional pressure regulator is
fitted).
NOZZLE SPACING:
This is equal to the spacing between the nozzle holders (1m or 0.5m).
Calibration
