Abstract
Ultrasonic emulsifying processes of immiscible liquids can be used to
obtain stable emulsions. The authors used an ultrasonic sandwich head with
an energy concentrator to obtain a suitable value of the energy density
necessary for the emerge of ultrasonic cavitation. Two piezoelectric ring
(Dext = 50 mm) transducers of Pz-26 type produced by FERROPERM were used
to design the ultrasonic sandwich head. The frequency of the ultrasonic
wave was 18.4 kHz and the excitation time of the ultrasonic transducer
exiting 5 minutes. Visible bubbles during the generation of ultrasonic
waves appeared in the mixture after exceeding the cavitation threshold.
The authors determined also the cavitation threshold by measuring the
electrical voltage conducted to the transducers. To receive long-lasting
emulsion, the electrical voltage attained 300 Vpeak. The dispersion
dependence on the emulsifying time was determined. The emulsion of linseed
oil and water was stable through some months without surfactants.
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