Abstract
A mechanical wave-guide is developed for transmitting and radiating high-frequency intense ultrasound by using a cylindrical solid rod whose diameter is large compared to the wave length. A piezo-electric thickness-mode vibrator is glued to one end of the rod as a electro-mechanical transducer, and ultrasonic power is radiated from the other end. The wave-guide is driven at the frequency of its coupled resonance to increase the vibration amplitude. Mechano-acoustic efficiency for water load is measured to evaluate the characteristics of the wave-guide in relation to its size and material. In a 9 cm-diameter aluminum-alloy rod, the efficiency is as high as 90 % at 500 kHz. Efficiency can be increased by reducing the transducer diameter. A wave-guide of 6 cm diameter and 37 cm length operates stably for a continuous electric input of 500 W. It is shown that this type of a wave-guide is an effective coupler which supplies high-frequency intense ultrasonic power to liquid material to be processed under severe environmental condition.
