Influence of more transducers in one generator on droplet size was
also determined. Liquid lever in generator and solution temperature were maintained constant
through whole process by continual re-filling and thermostat. Droplet size distributions were measured
without dilution of the aerosol and at same atomization and carrier gas parameters like in the
synthesizing process parametrs (Institute of Process Engineering in Life Sciences, Section I: Food
Process Engineering, Karlsruhe Institute for of Technology (KIT)). A laser diffraction system (Malvern
Spraytec) equipped with a 300 mm focusing lens was utilized for these investigations. Size
measurement by laser diffraction is based on the size dependent scattering angle of light at a droplet
or particle and therefore the scattering signal from the aerosol is detected in order to determine the
droplet size distribution. Generated aerosol is carried in the reaction zone with nitrogen flow rate
3,5-10 l/min. The reaction zone (quartz tube l=1,8m, d=42mm) is situated in furnace with three separate
regulated heating zone with temperature range 0-1100°C. So called “pre-heating” zone and
“cooling” zone are situated at entrance and exit of the furnace with length of 0,4m, and in the middle
is “reaction” zone with length 1m. Whole system was under inert atmosphere and small vacuum
(980mbar). Produced nanopowder was collected in electrostatic precipitator. For the characterisation
of the obtained titanium dioxide nanopowder was used scanning electron microscope.