“Ultrasonic” is generally defined as sound above the range of hearing, which for most people is any sound over 20 kHz or 20,000 cycles per second. The lowest frequency used in a commercial ultrasonic cleaner is typically 25 kHz, which suggests that an ultrasonic cleaner operates silently.
In fact, ultrasonic cleaners do create noise as the frequencies are converted to cavitation action that impacts not only the objects being cleaned but also the cleaning tank itself. As described by OSHA “Most of the audible noise associated with ultrasonic sources, such as ultrasonic welders or ultrasonic cleaners, consists of subharmonics of the machine’s major ultrasonic frequencies.”
The noise effect is most pronounced in ultrasonic cleaners operating at lower frequencies. For example, there is a noticeable difference between 25 kHz and 37 kHz. Units operating at 25 kHz are most often used in applications such as for cleaning, degreasing or deburring heavy metal products such as engine components. In contrast, the Elmasonic P line available from Tovatech is almost silent when operating at 87 kHz.
Companies employing personnel who operate low-frequency ultrasonic cleaners on a continuous basis should provide protection against potential hearing damage. For this reason hearing protection devices are widely used in such circumstances.
Equipment can be designed to reduce noise. Ultrasonic cleaners such as the dual-frequency Elma TI-H 25/45 models available from Tovatech, for example, come with an optional insulated hinged lid which in addition to dramatically reducing noise also improves thermal insulation.
Another option is to encase the cleaner with sound-deadening panels including a removable lid. This is most practical when the cleaning operation can be automated – i.e. with a timed cleaning cycle that automatically shuts off. Operators do not have to constantly attend the equipment and can direct their attention to tasks in other areas of the plant.
So, when it comes to dealing with audible noise generated by ultrasonic cleaners, “getting used to it” is not the answer. If the unit you purchase does not address this, hearing protection and applying sound insulation panels are recommended procedures.
Call on Tovatech’s ultrasonic cleaner professionals for help.
How do you protect yourself and your employees from potential hearing damage due to an ultrasonic cleaner?