Method and circuit for exciting an ultrasonic generator and the use thereof for atomizing a liquid
US4868521A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Aug 16, 1988 |
| Grant date | Sep 19, 1989 |
| Priority date | — |
| Expiry date | Aug 16, 2008 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB06B2201/77
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
A method and a circuit for exciting an ultrasonic generator comprises a control loop which includes the ultrasonic generator itself and a voltage-controlled oscillator. The control loop keeps the active power consumption to a desired value, which is compared in a comparator with the instantaneous active power consumption. One output of a further rectangular oscillator is connected to the control input of the voltage-controlled oscillator. The rectangular oscillator is put into operation if in the control loop there are no control oscillations or only those which are smaller than a predetermined threshold. The output of the rectangular oscillator is connected across one diode to the control input of the voltage-controlled oscillator and across another diode to the controlled input of comparator. The additional signal is applied to the voltage-controlled oscillator, apart from the control signal of the control loop. The cycle of the additional signal is longer than the change time constant at the control input of the voltage-controlled oscillator and the additional signal swing is selected in such a way that the frequency of oscillator passes through a predetermined frequency range.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.