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energy is transformed into mechanical energy. It does this by exciting the piezoelectric crystals
causing them to move in the longitudinal direction within the converter. This change from
electrical into mechanical energy causes a motion that travels through the horn/probe causing
the tip to move up and down.
The distance of one movement up and down is called its amplitude. The amplitude is adjustable.
Each probe has a maximum amplitude value. For example, with a 1/8” diameter probe at
se
tting 100%, the probe will achieve an amplitude of approximately 180μm. At setting 50% the
amplitude is approximately 90μm. Note: this is approximate and not perfectly linear. We
measure the amplitude of each probe at 100% and these values are published in the brochure.
Amplitude and intensity have a direct relationship. If you operate at a low amplitude setting, you
will deliver low intensity ultrasonic processing. If you operate at a high amplitude setting, you will
have high intensity ultrasonic processing. In order to be able to reproduce results, the amplitude
setting, temperature, viscosity and volume of the sample are all parameters that need to remain
consistent. The amplitude, not the power, is most critical when trying to reproduce ultrasonic
processing results.
Power has a variable relationship with amplitude/intensity. For example, sonicating water
requires less wattage when compared to a viscous sample (such as oil). While processing both
samples at the same amplitude setting, the power/wattage will differ because the viscous
sample will require more watts in order to drive the probe. The viscous sample puts a heavier
load on the probe, so they system must work harder to vibrate up and down at the same
amplitude setting. The oil may draw double the watts when operated at the same amplitude as
the water sample.
Small fluctuation in the wattage during ultrasonic processing is normal. Major swings in wattage
(+/- 20 watts) may indicate a problem with the sample, setup or the ultrasonic equipment itself.
Viscosity Limitations
Viscous solutions and highly concentrated liquids can be difficult to sonicate. If the liquid is so
thick that it cannot be easily poured out of a vessel, it is likely too viscous to be processed
ultrasonically.
Keeping Samples Cool
Ultrasonic processing causes the liquid temperature to elevate especially with small volumes.
Pulsed ultrasonic processing is always recommended. The addition of an ice bath or
recirculating chiller to cool the sample vessel is strongly suggested.
See website for more details and additional information:
