An Introduction to Ultrasonic Cleaning Systems

Multi-featured Elmasonic P Control Panel

Multi-featured Elmasonic P Control Panel

When setting out to purchase an ultrasonic cleaner for the first time it’s helpful to have an understanding of the various ultrasonic cleaner parts or components that comprise your sonic cleaner. This information will help you to select the equipment best suited to your cleaning tasks.

Ultrasonic Cleaning Tanks

Cleaning tank size – which also governs the cleaning solution capacity – must be sufficient to accommodate whatever you are cleaning.  This may seem a no-brainer but keep in mind that parts being cleaned must be fully immersed in the ultrasonic cleaning solution and should not be in contact with the tank – a condition that can damage parts and the tank walls and bottom due to ultrasonic vibration.

Cleaning tanks should be fabricated of cavitation-resistant stainless steel.  Look for rounded pressed or smoothly welded corners.  Drains facilitate removing spent solutions.

Most ultrasonic cleaning is accomplished in cleaning baskets, the dimensions of which are slightly under the tank length and width dimensions.  Baskets are sized to suspend parts above the bottom of the tank.  The distance from the bottom of the basket to the surface of the cleaning solution defines the working depth of the solution, which must be sufficient to completely immerse items being cleaned.  Note that while baskets are commonly suspended by handles resting on the tank rim others are equipped with rubber-coated feet positioned near the corners of the tank bottom where there is minimal vibration.

Industrial ultrasonic cleaners may be fitted with racks on which parts can rest during the cleaning cycle. Parts can be lowered into the cleaning solution by an overhead suspension system.

Tanks should be equipped with lids that reduce operation noise and cleaning solution evaporation.  Certain cleaner models have lids that when inverted double as drain trays for parts after baskets are removed from the cleaning solution.  Industrial units may have insulated lids offered as an option.

Ultrasonic Generators and Transducers

Ultrasonic generators convert normal 60-cycle (60 Hz) AC current to the frequencies required by the ultrasonic transducers that in turn create the cavitation bubbles in the cleaning solution.  Generators can either be in the ultrasonic cleaner housing or be remotely located. A related topic is ultrasonic power.  Frequency and power, while not strictly “components” of a cleaning unit, are important specification considerations.  We direct your attention to our post on selecting frequency and power.

Ultrasonic transducers are components of the equipment and their frequencies determine the intensity of cleaning action.  Transducers are either bonded to the tank or can be immersed in the solution.  For a detailed discussion on this topic please check our post introducing ultrasonic transducers.

Ultrasonic Cleaner Instrumentation

Ultrasonic cleaner controls range from a simple on-off ultrasound switch to controls for solution heating, cleaning cycle timing, the sweep mode, pulse mode, degas mode, pause and adjusting ultrasonic power.  Many of these sophisticated units have LED displays showing which functions are in play, and indicate selected frequency, selected power, and set and actual solution temperature and cleaning time.   As a safety factor some ultrasonic cleaners have an auto shutoff after a certain time such as 12 hours of operation to avoid potential equipment damage.

Ultrasonic Cleaning Solution Maintenance

Contaminants removed during the ultrasonic cleaning process end up in the solution and eventually degrade its performance, necessitating replacement.  For small tabletop units a good practice is to skim off and properly dispose of contaminants that float to the surface.  Larger cleaners may have sprayers and skimming weirs that direct floating contaminants into oil skimmers or oil separators for either disposal or recycling.  Contaminants that drop to the bottom of a tank can be directed through filtering mechanisms that return treated solution to the tank.  Our post on skimmers and filters goes into this topic in more detail.

These, then, are key components that together comprise an ultrasonic cleaning system.  Not included are rinsing sprays, rinsing tanks and dryers, details of which are found elsewhere in our blog.  Please feel free to contact Tovatech’s ultrasonic cleaning professionals to discuss your cleaning requirements and for recommendations on equipment and procedures.

About Rachel Kohn

So how did an MIT Ph.D. end up selling refrigerators? When I figured out that a lot more scientists buy lab refrigerators than innovative leading-edge instruments. I hope that my many years of lab experience will help you find the right equipment for your work. Before co-founding Tovatech I worked in business development and project management at Smiths Detection, Photon-X, Cardinal Health, and Hoechst Celanese. And before that I spent 12 years as an R&D chemist at Hoechst Celanese and Aventis working on advanced drug delivery systems, polymer films and membranes, optical disks, and polysaccharides. Some day, eventually, I’ll make enough money to develop an innovative technology that will change the world. Read More