Ultrasonic cleaning : How to choose?

Kind of ultrasonic cleaning transducer

Transducers fixed to the outer wall of the tank, plates fixed and ultrasonic immersible boxes have the same cleaning effect: the ultrasound field goes from the vibrating membrane in the liquid in a directive way.

Ultrasonic transducers are typically used for small tanks and can be easily placed on different walls of the tank, facing the areas to be cleaned.
Submersible boxes are recommended for medium and large tanks, as they are quickly installed, and facilitate maintenance.
Plate transducers may also be replaced, and do not take up any space in the tank. But they require a pre-cutting of the tank.

Regarding radial rod transducers, they create ultrasound vibrations at 360 ° along the probe. This type of transmitter is thus relevant to clean hollow parts or for integration into a tank with a rotating basket. The probe is made of mass titanium and can be used for cleaning by immersion with a pressure of a few bars.

Ultrasonic cleaning frequency

Lower frequencies, between 20 and 30 kHz, create rather powerful cavitation bubbles having a size of about 150 microns. This is the most common frequency range, which is used for most industrial applications.

By increasing ultrasonic frequency, the bubble size decreases, and micro-jets energy is lower. Noise level is lower. Cleaning systems with a frequency of at least 40 kHz are rather used for cleaning of delicate parts.

Ultrasonic power and distribution of ultrasonic cleaning transducers

Power is related to the number of ultrasonic cleaning emitters used. The more the tank and parts to be cleaned are big, the more it is necessary to put power. The power density of an ultrasonic bath is between 10 and 20 W / L for smaller tanks and between 5 and 10 W / L for larger ones.

The arrangement of parts in the basket and the orientation of the ultrasonic cleaning transducers must be done, so that the ultrasonic field is not blocked by a screen of pieces in the foreground, regarding other parts located behind. For cleaning small parts in a jumble, it is better not to put too many parts or you can use a rotating basket to mix the parts.

The parameters affecting the efficiency of ultrasonic cleaning

• The power and the distribution of the ultrasonic field, according to the parts,
• The ultrasonic cleaning transducer  frequency,
• Bath temperature : typically between 40 and 60 ° C ,
• The detergent to facilitate the cleaning ,
• The ultrasonic cleaning duration varies between a few seconds and a few hours.