Agriculture Reference
In-Depth Information
gallons or more per minute. Because the application rate is usually 100 gal-
lons per acre or more, large tanks (500 to 1,000 gallons) are used.
Mechanical agitators are usually standard equipment, but hydraulic agita-
tors may be used. When fitted with correct pressure unloaders, these sprayers
can be used at low pressures. All hoses, valves, nozzles, and other compo-
nents must be designed for high-pressure applications. High-pressure sprayers
may be equipped with a hose and single handgun nozzle for use in spraying
trees and animals. These sprayers are also fitted with a boom for agricultural,
ornamental, nursery, and aquatic applications. Figure 8.11 shows several pic-
tures of worker with high-pressure sprayers.
Advantages:
provide good penetration and coverage of plant surfaces
usually well built and long lasting if properly cared for.
Limitations:
high cost
large amounts of water, power, and fuel needed
high pressure may produce fine droplets which drift easily.
3.
Air Blast Sprayers
Air blast sprayers use a combination of air and liquid rather than liquid
alone to deliver the pesticide to the surface being treated. They are used in ag-
ricultural, ornamental and turf, biting fly, forestry, livestock, and right-of-way
pest control operations.
These sprayers usually include the same components as low-pressure or
high-pressure sprayers, plus a high-speed fan. Nozzles operating under low-
pressure deliver spray droplets directly into the high-velocity airstream. The
air blast shatters the drops of pesticide into fine droplets and transports them
to the target. The air blast is directed to one or both sides as the sprayer
moves forward, or it may be delivered through a movable nozzle.
Most air blast sprayers are trailer-mounted, but tractor-mounted models are
available. Tank capacity ranges from 100 to 1,000 gallons. Most of these
sprayers can be adapted to apply either high or low volumes of spray material
as well as concentrates. Mechanical agitation of the spray mixture is com-
mon. An air blast sprayer may cover a swath up to 90 feet wide and reach
trees up to 70 feet tall (see Figure 8.12 ) .
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