To effect such, the object to be cleaned must be rotated, completely under the surface, if necessary, to discharge any pockets of air or gas such that the gas rises out of the bath. Not doing so allows energy to be dissipated in the degassing phenomenon and not to be available for the cleaning process. A still tank can be activated by insertion of an immersible transducer into the bath. Cavitation in the tank creates shock waves and cleans surfaces of parts and assemblies by accelerating detergency of cleaning agents in the bath and by mechanically blasting contaminants off the surfaces. There is a sizeable overlap in sizes and applications for the two styles.
Larger units are generally custom built.
An immersible transducer placed in a still tank turns that tank into an ultrasonic cleaner. An ultrasonic vapor degreaser adds ultrasonics to the heated tank. The cleaning solvent was pumped under pressure backward through the porous filter medium, usually sintered pleated wire mesh cylinders, to flush away contaminant and the unit provided means for performing bubble testing for maximum pore size determination and differential pressure testing for cleanliness evaluation. Since then various other devices have been developed for like use. For terminology, see the Ultrasonics Glossary page.