Angling Of Air And Nozzle Flow, Rules Of Thumb; Water Sensitive Paper - Hardi ALPHA evo EcoDrive TWIN FORCE Instruction Book

4 - Sprayer setup

Angling of air and nozzle flow, rules of thumb

To control wind drift the influence of wind speed and wind direction as well as the horizontal air current around the boom
due to forward speed must be minimised. Because it is a sum of two forces with variable direction and size that we have to
counteract for, the following can only be very rough guidelines.
Wind direction:
Head wind: Angle forward.
Tail wind: Angle back (if the forward speed is higher than the wind speed: angle forward).
Side wind/no wind: Angle vertical or back. Only high forward speeds may require forward angling.
Types of crops:
Bare ground/low vegetation: Low air speed and angling back will often be the best setting to avoid reflection of spray liquid.
Dense crops: The angling feature is ideal to help open the canopy and improve penetration. If you follow the crop
movement as you are varying the angling you will find the right setting.
If the wind speed, wind direction or forward speed changes during spraying, the angling must be
changed too. With certain combinations of air flows and angling there is a risk of "closing" or flattening the crop and making
penetration impossible - follow the crop movement intensively, especially when adjusting the air assistance and keep an
eye on the crop throughout the spraying operation.
• It is essential for the operator to be familiar with the basic rules above before using the TWIN.
• All volume rates, pressures and air adjustments stated in the following tables are given for information purposes.
Special conditions regarding climate, crop type, spraying positioning and chemical applied can change this
information. The tables show practices in northern Europe, and conditions may be very different in other countries. If
you want some local advice, please contact the TWIN application expert in your country.
• As a general rule, the application volume may be half of the application volume used with a conventional sprayer, with
a minimum of 50- 60 l/ha at 7-8 km/hr. This does not apply to weedkillers and liquid fertilisers whose selectiveness is
based on large droplets that only cling to weeds.
• Drift limitation nozzles can also be used on a TWIN. They contribute to reducing drift.
• Observe all specific instructions about droplet size, operating pressure, application volume etc. that may appear on the
label of the product used.
μ
ATTENTION! It will sometimes be necessary to drive with two different anglings, so the angling is changed when
making a half turn at the end of the field.

Water sensitive paper

USE PAPER THAT IS SENSITIVE TO WATER TO HELP FIND THE BEST AIR SETTING.
The best way to learn to use the TWIN is to conduct tests with clean water on different crops, checking the application with
paper that is sensitive to water. The paper can be cut into smaller pieces and fixed with double sided tape at relevant places
in the crop to simulate the target. Then spray with clean water and check the blue spots (droplets) on the paper. This way
you can test different application techniques. Moisture-sensitive paper is available at your local HARDI dealer, part No.
893211.
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