The mechanism and possible applications of drying by ultrasonic irradiation

Abstract Drying by irradiation with ultrasound has yet to be widely adopted by industry, although its ability to dry at constant temperature would make it valuable for materials which deteriorate under heating and for chemicals with long drying cycles. The author suggests reasons for this delay and outlines how ultrasonic drying occurs by the interaction of two diffusion currents, one thermal and one due to concentration. He gives figures to show its effectiveness in drying sugar and outlines a theoretical treatment. The changes that ultrasound causes in the two diffusion currents are the mechanism of ultrasonic drying. The author examines this mechanism and the factors which influence it and relates his theory to the dimensions of the material being dried and the variables of the acoustic field