In our last blog we explored a fundamental phenomenon related to ultrasonic cleaning: frequency. We arrived at the observation that lower frequencies produce relatively larger and higher energy cavitation bubbles, and higher frequencies produce smaller bubbles that are able to penetrate into smaller areas. We saw that the most common frequency compromise between scrubbing power and cleaning penetration is found at 40khz.
However, while this is certainly one good takeaway from the study of frequency in ultrasonic cleaning applications, UPC wanted to come up with a solution that worked well to incorporate multiple frequencies into the cleaning process, to better take advantage of the different ways in which the different frequencies work. The result is our Vibra-Bar®technology that reliably produces multiple frequencies simultaneously (Simultaneous Multi-frequency®). While the advantages of such an arrangement may be apparent, the technique for the creation of these frequencies is less readily so.
The typical shape of a vibrating membrane to produce sound waves is a circle – think drum heads, and audio speakers. The advantage of a round shape is that it produces a more uniform signal dispersion to minimize distortion. However, for cleaning purposes (that are out of range of the human ear), distortion is actually desired because it is the very presence of multiple resonant frequencies that is advantageous. The rectangular shape of our Vibra-Bar® and its structural design allows Simultaneous Multi-frequency® resonance even though only one (40khz) is supplied to the piezoelectric stacks. This happens because of the complex resonant properties of a three dimensional rectangle shape, when driven by two separate piezoelectric stacks.
The technology behind UPC’s flagship product is certainly complex, but the results are clear: faster operation, deeper cleaning, less erosion, higher reliability, and wider range of cleaning capability. At UPC, we’re continually pursuing new and innovative ways to help our customers get the most out of this technology, and our Vibra-Bar® design providing Simultaneous Multi-frequency® is just a manifestation of that pursuit.