Twisted transducer

Regardless of the type of transducer used, the most fundamental factor is usually the intensity of the cavitation effect it produces. Ultrasound, like other sound waves, is a series of pressure points, namely a wave that alternates between compression and expansion (as shown in the figure below). If the sound energy is strong enough, the liquid is pushed away during the expansion stage of the wave, resulting in bubbles; During the compression stage of the wave, these bubbles instantly burst or implode in the liquid, producing a very effective impact force, particularly suitable for cleaning. This process is called cavitation.
However, cavitation only occurs in a certain area when the liquid pressure is lower than the gas pressure inside the bubble. Therefore, this condition can only be met when the ultrasonic amplitude generated by the transducer is sufficiently large. The small power required to generate cavitation is called the cavitation critical point. Different liquids have different cavitation critical points, so ultrasonic energy must exceed this critical point to achieve cleaning effect. That is to say, only when the energy exceeds the critical point can cavitation bubbles be generated for ultrasonic cleaning.
At the beginning of the 20th century, the development of electronics enabled people to use the Piezoelectricity and magnetostrictive effect of some materials to make various electromechanical distortion transducers. In 1917, French physicist Langevin made a sandwich ultrasonic transducer from natural piezoelectric quartz and used it to explore submarines on the seabed. With the continuous development of ultrasonic applications in various departments of military and national economy, there have been more magnetostrictive transducers with higher ultrasonic power, as well as various types of ultrasonic transducers with different uses, such as electric, electromagnetic, and electrostatic transducers.
The commonly used transducers for ultrasound are divided into magnetostrictive transducers and electrostrictive transducers based on the vibration excitation method. If the ultrasonic energy is large enough, cavitation phenomenon will occur everywhere in the cleaning solution, so ultrasonic can effectively clean small cracks and holes. Cavitation also promotes the chemical reaction and accelerates the dissolution of the surface facial mask.
Theoretically, a burst cavitation bubble will generate a pressure exceeding 10000 psi and a high temperature of 20000 ° F (11000 ° C), and the shock wave will rapidly radiate outward at the moment of its burst. The energy released by a single cavitation bubble is very small, but millions of cavitation bubbles burst simultaneously every second, and the cumulative effect will be very strong. The strong impact force generated will peel off the dirt on the surface of the workpiece, which is the characteristic of all ultrasonic cleaning.