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Title: Laboratory and field evaluation of the narrow spectrum Unimizer Nozzle
Authors: Dorr, Gary
Keywords: nozzle calculator
centrifugal energy nozzle
aerial application
pesticide application
reduce pesticide spray drift
low range of droplet sizes
Unimiser nozzle
hydraulic nozzles
enable prediction of droplet size
Issue Date: 30-Jun-2003
Publisher: University of Queensland
Series/Report no.: ;UQ33C
Abstract: Unispray have developed a new centrifugal energy nozzle, the "Unimiser", for the aerial application of pesticides. The new nozzle is designed to substantially resulting from the aerial application of pesticides in the cotton industry. The nozzle was designed to generate a very low range of droplet sizes, (having a relative span of less than 0.8 compared with 1.2 -1.6 for most currently available nozzles) and a volume median diameter of 250 pm, Testing of prototype models have demonstrated that that the Unimiser nozzle is able to generate a narrower range of droplet sizes, as indicated by a lower span, than any other commercially available alternative. It is expected that drift from this nozzle is likely to be lower than for other nozzle used on aircraft in the cotton industry. During the course of this project Unispray decided to initially concentrate on a Helicopter version of the initial prototype. The results from the single flight line deposit measurements showed that there was a consistent area of low deposit beneath the centre-line of the helicopter. Since it was impractical to mount an air driven rotary nozzle in the slow moving air close to the airframe beneath the centre line of a helicopter, a small number of additional hydraulic nozzles were fitted. This small modification improved the uniformity of the deposit. The tests showed that more uniform ground deposit patterns were obtained when three Unimiser nozzles were operated on each side of the helicopter. Based on results from the wind tunnel studies, pattern testing and market requirements, Unispray decided to concentrate on a "retro fit" version that can easily be added to existing Micronair units. Droplet size was measured over the range of nozzle rotational speeds, liquid flowrates and airspeeds that are likely to be encountered in the field. Testing was initially undertaken with water only but was later repeated with a Water + 0.1% Agral mix. The Agral was added as it is oflen considered to be more representative of an actual tank mix. In general a slightly larger range of droplet sizes (larger span) was generated with the Water + Agral mix. From the measurements a regression analysis was undertaken to enable prediction of droplet size using the range of variable tested in the wind tunnel From this analysis an EXCEL based "nozzle calculator" was developed and a full working copy of the calculator has been included with this report.
Appears in Collections:2003 Final Reports

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