Principles Of Operation - Omni Q55 Ultrasonic User Manual

4. PRINCIPLES OF OPERATION

The Q55 ultrasonic electronic generator transforms DC line power to a 20 KHz signal
that drives a piezoelectric converter/transducer. This electrical signal is converted by
the transducer to a mechanical vibration due to the characteristics of the internal piezo-
electric crystals.
The vibration is amplified and transmitted down the length of the probe where the
tip longitudinally expands and contracts. The distance the tip travels is dependent on
the amplitude/intensity setting selected by turning the output control knob. As you
increase the amplitude setting the sonication intensity will increase within your sample.
In liquid, the rapid vibration of the tip causes cavitation, the formation and violent col-
lapse of microscopic bubbles. The collapse of thousands of cavitation bubbles releases
tremendous energy in the cavitation field. The erosion and shock effect of the collapse
of the cavitation bubble is the primary mechanism of fluid processing.
The probe tip diameter dictates the amount of sample that can be effectively processed.
Smaller tip diameters deliver high intensity sonication but the energy is focused within
a small, concentrated area. Probes with larger tip diameters can process larger volumes,
but offer lower intensity.
The choices of a power supply and horns/probes are matched to the volume, viscosity,
and other parameters of the application. Horns are available for both direct and indirect
sonication. See section 10 for more information on this subject.