An ultrasonic jewelry cleaner operates by creating high-frequency waves in a liquid. The jewelry to be cleaned is placed in this liquid, where the rapid motion of the water creates very small bubbles that hit the surface to be cleaned and knock any dirt to the bottom of the liquid's container. Some ultrasonic jewelry cleaners require a type of special cleaning fluid to help remove dirt more effectively, while others require only water. Many types of jewelry made from hard metals can be cleaned in an ultrasonic jewelry cleaner, but some delicate designs and gemstones could be broken if run through such a machine.
The basic mechanism used in an ultrasonic jewelry cleaner is a device that creates a high-frequency sound called a transducer. This signal enters the liquid, which needs to be viscous enough for the waves to move through it quickly, and begins to generate very small bubbles. The higher the frequency of the sound, the smaller the bubbles will be. These bubbles move through the liquid and hit the surface of the jewelry to be cleaned, causing the dirt to fall away.
For certain types of stains and dirt on jewelry it might be necessary to use a liquid cleaner in the water. This can prevent having to run a piece of jewelry through an ultrasonic cleaner repeatedly until the stains are slowly removed. A lower-powered ultrasonic jewelry cleaner might require a cleaning liquid to work properly. These can be simple ammonia solutions or more complex solvents.
The ultrasonic waves that are emitted into the water only contact the jewelry for a few minutes at a time, depending on the design of the machine. Very powerful ultrasonic jewelry cleaners can actually cause damage to fragile jewelry or gemstones. Specifically, stones such as pearls can be damaged by an ultrasonic cleaner. Similarly, jewelry that is very fragile or very delicate in construction could be harmed. Leaving jewelry in the cleaner for longer than the recommended cycle time also can cause damage.
Some ultrasonic jewelry cleaners have very simple designs, consisting only of a transducer, a timer and a bin to hold the water; this is where the jewelry is placed for cleaning. Other designs are more complex, providing trays that allow jewelry to be secured in place before being lowered. Some designs even come with a mechanism that slowly spins inside the liquid, so pieces such as bracelets can be attached and then rotated as they are cleaned.
