80
Code F07012287
USE AND MAINTENANCE
ENGLISH
Fig. 143
6.8.1.3 ANTI-DRIFT NOZZLES
There are different models of nozzles limiting the effect of
drifting. The main feature consists in eliminating the mist
effect due to the presence of excessively small droplets,
subject to drift.
ATTENTION
Use beyond the permitted limits affects the precision
and duration of the nozzle.
The density and specific weight affect the flow rate of the
nozzles.
Example: To distribute a mixture which specific weight is
greater than water, a nozzle with higher rated flow-rate
(than water) must be selected. Should you wish to deliver
the same amount, you need to select a nozzle that deliv
-
ers 15% more. In practice, if the nozzle carries 1 l/min
with water, with a denser and heavier mixture (1.32 kg/l) a
nozzle with a flow rate of 1.15 l/min must be used to sup
-
ply 1 l/min of mixture.
6.8.2 TECHNICAL INFORMATION ON
NOZZLES
The choice of a nozzle is often based on droplet size. The
size of the droplets dispensed by a nozzle is extremely
important when the effectiveness of a particular chemical
product depends on the coverage or when the dispensed
liquid must not disperse far from the target. Most nozzles
used in agriculture can be classified on the basis of the
production of fine, medium, coarse or very coarse droplets
(see table below).
The nozzles that produce fine droplets are normally rec
-
ommended for post-emergency applications that require
excellent coverage of the area to be treated. The most
commonly used nozzles in agriculture are those that
produce medium-sized droplets. The nozzles that produce
medium and large-sized droplets may be used for contact
and systemic herbicides, herbicides applied to the surface
in pre-emergence, insecticides and fungicides. When
choosing a nozzle that produces a droplet dimension in
one of these six classes, it is important to remember that
the same nozzle may produce droplets of different sizes
at different pressures. A nozzle may produce medium
droplets at low pressure, but if the pressure increases, it
may produce fine droplets.
The droplet dimensions are classified based on BCPC
parameters and according to ASAE standards, S-572 at
the time of printing.