A History of Air-Blast Sprayer Development and Future Prospects

Abstract

The design and operating procedures of air-blast sprayers have been greatly improved over the past 50 years. Early tree and vine spray application equipment used hand-guns that required a large amount of water. Later, sprayers with efficient fans, producing large volumes of air at high velocities, were developed for large fruit and nut trees. Recently, apple growers have planted many dwarf and semi-dwarf trees. In general, it is easier to produce more uniform coverage with less drift when spraying small trees than when spraying large trees. Modern designs such as tower, directed jet, and tunnel sprayers should reduce airborne spray drift and produce more uniform coverage. For optimum effectiveness, sprayer air-jet velocity, volume, and droplet spectra should be matched to the tree size, shape, and density. Besides optimizing delivery parameters, future sprayers will likely be required to handle biological materials with a greater variety of physical properties than the standard chemical materials used now. In addition, these materials will require spray systems that protect the live spray products from damage from heat, mechanical stress, and other factors that may kill the beneficial organism being applied.