Ultrasonic Transducers
Ultrasonic transducers are the power source of larger cleaning systems that convert electrical energy from a generator into mechanical energy, or sound vibrations, which cause cavitation. Cavitation is the formation of bubbles in the cleaning systems, which implode and scrub the surface of parts. Transducers are one of three main components of ultrasonic cleaning systems, and are usually mounted on the bottom or the largest side of the tank to allow the highest distribution of sonic energy throughout the cleaning system. These transducers can reach 20 to 40 kHZ and are too powerful for portable cleaning systems like at-home jewelry cleaners, which are battery powered. There are two main types of ultrasonic transducers used today-piezoelectric transducers and magnetostrictive transducers. Each is equally effective and yield similar results but use dramatically different methods.
The piezoelectric transducer is composed of a lead zirconate crystal that is placed in between two tin strips. The voltage applied to the strips from the generator creates displacement in the crystal, which causes a pressure wave. The wave is transmitted through the tank, causing high frequency vibrations. This method is inexpensive and efficient, but doesn't last long in heavy-use situations because the crystal depolarizes itself. Magnetostrictive transducers contain nickel laminations which form a stack and are tightly connected with an electrical coil. As the current from the generator flows through the transducer, the coil creates a magnetic field with an alternating current, and the nickel stack vibrates, causing cavitation. This method is used more in industrial applications since it is stronger, more durable and longer lasting than the piezoelectric transducer. However, it is not as efficient.