Patent ID: 7211928
Filing Date: 2007-05-01
Classification: B01J,B06B,B08B,G10K

Abstract:
1. A system for coupling ultrasound to a liquid, comprising: one or more transducers adapted for coupling to a liquid, the transducers constructed and arranged so as to be capable of producing ultrasound in the liquid at frequencies within at least two frequency bands, and, an ultrasound generator adapted for producing a driver signal for driving the transducers at frequencies in one or more frequency ranges within each of the at least two frequency bands; wherein the driver signal of the ultrasound generator drives the transducers to produce ultrasound in the liquid characterized by successive frequencies within at least one of the frequency ranges in one of the at least two frequency bands; and, wherein the ultrasound generator has an output stage, which comprises a) modification circuitry which modifies the output stage; b) an AC switch, operatively connected to the modification circuitry, which switches the modification circuitry into and out of the output stage of the ultrasound generator; and c) control circuitry, associated with the AC switch and with the ultrasound generator, which is adapted to turn off and turn on the AC switch, wherein the control circuitry, AC switch and modification circuitry changes the ultrasound generator driver signal to further drive the transducers to change frequency to a different frequency range in a different frequency band, so as to generate ultrasound characterized by successive frequencies within at least one additional frequency range in at least one additional frequency band of the at least two frequency bands; and, wherein the driver signal can be divided into a succession of time periods with at least one time period where the predominant form of cavitation in the liquid is stable cavitation and at least one of the successive time periods where the predominant form of cavitation in the liquid is transient cavitation.