How to use Airblast Nozzle Tables

The author looking up nozzle rates during a spring calibration. The operator was running at 190 psi, but the catalogue only listed 180 psi and 200 psi. When span is only 20 psi, it’s fairly safe to approximate the output. When the table only lists in 50 psi increments, it is more difficult to determine the rate without testing the output. This issue usually occurs at pressures above 200 psi, and that’s very high for most horticultural operations. Consider using a lower operating pressure, if possible.

Airblast operators should know how to read a nozzle table. They are found on dealer and manufacturer websites as well as in their catalogs. Table layout varies with brand, but they all relate a nozzle’s flow rate to operating pressure. The better tables also provide the spray angle and the median droplet size (i.e. spray […]

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The pressure/spray/coverage relationship

Pressure is integral to nozzle performance. Reducing hydraulic pressure reduces nozzle flow rate, increases median droplet size, and typically reduces spray fan angle. Increasing pressure increases nozzle flow rate, reduces median droplet size and typically increases spray fan angle. You can watch this Exploding Sprayer Myths video to learn how pressure, boom height and nozzle spacing […]

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Validate airblast output – nozzle calibration

The SpotOn SC-4 calibration vessel is much easier, faster and more accurate than the classic pitcher-and-stopwatch approach to timed output tests.

Sprayer math is important. It ensures the operator applies the correct product rate and has enough to complete the job. But, it assumes the airblast sprayer is behaving as expected… and it often doesn’t. After confirming the airblast travel speed, use one of the following methods to assess sprayer output. There are pros and cons […]

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Airblast Nozzle Bodies

A typical brass roll-over style dual nozzle body with Cap and optional check valve.

Excepting air shear and centrifugal style nozzles, most airblast sprayers employ nozzle bodies distributed evenly along the booms. Nozzle caps compress the nozzle against the body to force the spray mix through the nozzle orifice. Nozzle bodies are not all created equal. Double Outlet Roll-Over Nozzle Bodies Double outlet roll-over bodies (pictured below) allow the […]

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How Airblast Spray Droplets Behave (or Misbehave)

Some pesticide labels require or prohibit certain droplet sizes to reduce the potential for drift. But, even when labels are silent about size restrictions, operators should be aware of the potential for droplet size to affect coverage. In the case of airblast, droplets should be: large enough to survive evaporation between nozzle and target. small […]

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