Industrial requirements in high-power ultrasonic transducers for defoaming

Abstract

Airborne stepped-plate focusing transducers have shown to be an efficient tool for breaking foams. The main characteristics of such transducers are their high efficiency and power capacity as well as their strong focusing effect. As a consequence, by using these power transducers it is possible to generate intensities in the focal area as high as 170 dB. However, for their application to industrial problems a special design has to be done covering specific requirements. The main requirements for industrial applications refer to efficiency, safety, durability and environmental resistance. This paper deals with the design and characterization of an industrial prototype of high power ultrasonic transducer for defoaming which is able to work in continuous operation under adverse environmental conditions, and high power excitation without the use of any cooling system. In addition, the transducer is designed to ensure the safe use of airborne high-power ultrasound according to the international recommendations for occupational exposure limits.

The industrial use of the transducers is for defoaming in bottling and canning lines and in fermenting vessels and other reactors.