Selecting the correct nozzle is one of the most crucial,
yet overlooked, elements in irrigation system design.
Choosing the correct nozzle, whether it's for a spray head
or a rotor, is easy if you take the time to study the nozzle
charts in a manufacturer's product catalog and select one
that best suits your needs; irrigation equipment manufacturers
have put a tremendous amount of effort into developing nozzles
to fit almost every application:
For slopes and compacted soils, select a nozzle with a
lower precipitation rate.
For windy areas, select a nozzle with a low nozzle outlet
trajectory.
To achieve even water distribution without having to separate
part-circle from full-circle sprinklers, select a nozzle
set that features a matched precipitation rate.
Another way to ensure uniform watering, if you're working
with spray heads, is to select nozzles that have an undercut
nozzle. These nozzles have an second, undercut orifice for
watering closer to the head.
For flexibility with spray heads, select a nozzle with
an adjustable or variable arc.
Because nozzles are designed to work within a wide range
of pressures, it is important to ensure you have the correct
pressure at the base of the nozzle. Too much pressure, as
is commonly the situation with spray heads, will result in
misting. Misting creates a reduction in the radius of throw
and you may experience uneven coverage, and cause wet and
dry spots. To correct this, several manufacturers offer devices
that can be installed at the nozzle or are integrated in the
sprinkler, such as the Rain Bird PRS Series.
If you're working primarily with rotors, keep in mind that
too much pressure can cause the rotor to rotate too quickly.
The nozzle stream of a fast moving rotor will "horsetail"
and cause a severe reduction in the radius of coverage. Too
little pressure will also result in a reduction in the radius
of throw and uneven water distribution.
For more information on proper nozzle selection, contact
Rain Bird Technical Services at (800) 247-3782.
