Ultrasonic cleaning baths are widely used in industrial production for cleaning and degreasing metallic components and are also available for private use for cleaning jewelry and glasses. The cleaning process is based on the cavitation in the cleaning medium (water, if necessary with cleaning additives) caused by ultrasonic waves: due to high acoustic pressure, steam bubbles form which disintegrate spontaneously or after several oscillation cycles. The resulting pressure waves and currents tear dirt particles from the surfaces to be cleaned. In addition, the cavitation favors the distribution of the contaminants in the cleaning medium. It is also possible to produce stable oil-water emulsions.
In the public funded research project "Mobile cleaning unit for conveyor chains based on ultrasound", together with two industrial companies it was examined whether conveyor chains, which are mounted on the hall ceiling in the industrial area and used for the transport of hanging goods, can be cleaned more efficiently with the ultrasonic circulation process than with conventional systems such as high pressure or steam jets.
The cleaning process essentially depends on the intensity and distribution of the sound field in the process room. Other parameters are the gas content of the cleaning medium, the frequency of the vibrations and the temperature. In order to achieve an optimal cleaning result efficiently, these factors must be taken into account when designing the process room. The ultrasonic transducer must be matched to the process and, if possible, be controlled. This was achieved with various modeling approaches and simulations as well as their comparison with experiments.
Individual heavily soiled chain links could be successfully cleaned in the assembled prototype, but the industrial implementation did not take place due to the high investment costs.