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• PROBLEM
• Reduction of the water volume rate is an
  important aspect to reduce appli-cation cost. The
  water reduction per unit area increases the total
  capacity of a sprayer but normally is linked to
  reduced droplet size and increased drift
  potential. One possibility to reduce water volume
  rate with less effect on drift is to use a rotary
  atomizer with a narrow dropled size spectra.

• OBJECTIVES
• The main objective of this current study is the
  investigation of spray character-istics and
  dynamic air velocity of a hydraulically driven
  cage atomizer integrated in an axial blower
  (Proptec PT100) under laboratory conditions.

• MATERIAL AND METHODS
• The rotary atomizer was operated from 500 rpm to
  4000 rpm by steps of 500 rpm
• Flow-rate increase from 0.7 l/min to 1.3 l/min by
  steps of 0.2 l/min corresponding to water volume
  rates of 100, 150, 200, 250 l/ha with four rotary
  atomizers in the experimental sprayer
• Blade angle adjustment of the axial fan between
  25 and 45 in five steps
• Anemometer (Testo 445) was fixed 0.18 m off
  centre and at distances from 0.2 m to 1.2 m by
  steps of 0.2 m. Data acquisition system connected
  to a PC
• Droplets spectra measured by a Malvern
  Instruments Master Particle Sizer

• RESULTS AND DISCUSSION
• The coupling of axial blower and cage atomizer is
  linked with some restrictions concerning air
  velocity and oil pressure
• Setting is variable between 2000 and 4000 rpm for
  similar air speed and oil pressure by blade angle
  adjustment
• Reducing rotational speed below 2000 rpm is
  linked with decreasing air speed
• Application of living organisms with 1000 rpm
  requires a separate drive for the blower
• There is no significant influence of flow rate on
  droplet size.

REFERENCES Fleming, G.A. (1962) The relationship
of air volume, air velocity and droplet size to
the efficiency of spray transport in air blast
spraying. PhD. Thesis, Cornell Univ. 66 pp. Hall,
F.R., D.L.Reichard, and H.R. Krueger (1977)
Dislodge able azinphosmethyl residues from air
blast spraying of apple foliage in Ohio. Archives
of Environ. Contam. 3352-363. Ras, M.C.D. (1991)
Principles for the integration of air
characteristics from mistblowers with penetration
into tree structures. In BPCP Mono. 46,
Air-Assisted Spraying in Crop Production, Levers,
A, et al., Eds., 287-295. Reichard, D. L., R. D.
Fox, R. D. Brazee, and F. R. Hall (1979) Air
velocities delivered by orchard air sprayers.
Transactions of ASAE 22(1)69-74, 80. Walklate,
P.J., K.L.Weiner and C.S. Parkin (1996) Analysis
of and experimental measurements mad on a moving
air-assisted sprayer with two-dimensional
air-jets penetrating a uniform crop canopy. J.
Ag. Eng. Res. 63365-378. Matthews, G. A. (1992)
Pesticide Application Methods. 2nd Edition.
Longman Scientific and Technical. London and New
York.
Prof. Dr. Siegfried Kleisinger, University
of Hohenheim, Institute of Agricultural
Engineering (440) - VIK, D-70599 Stuttgart,
Germany, kleising_at_uni-hohenheim.de Sehsah ,
El-Sayed (Ph.D.student) , University of
Hohenheim, Institute of Agricultural Engineering
(440) - VIK, D-70599 Stuttgart, Germany,
ssehsahm_at_uni-hohenheim.de Dr. G. Baecker,
Viticulture Research Institute Geisenheim,
von-Lade-Str.1D-65366 Geisenheim, Germany,
G.baecker_at_fa-gm.de Dr. Zbigniew Czaczyk,
August Cieszkowski Agricultural University of
Poznan, Institute of Agricultural Engineering.,
Wojska Polskiego 50, 60-627 Poznan, Poland,
czaczykz_at_au.poznan.pl
International Conference Environmentally
Friendly Spray Application Techniques. Warsaw,
Poland, 4.- 6. October 2004