How to Safely Operate an Ultrasonic Cleaner
Safely operating an ultrasonic cleaner is a broad subject covering more than just turning the unit on and proceeding with a cleaning cycle. Good safety practices apply to any size ultrasonic cleaner - whether used in the home, the research lab or on the industrial floor. They begin upon receipt of your ultrasonic cleaner by, of all things , reading the operators manual to become totally familiar with all phases of the cleaning equipment and its operation.
By doing so you are on the way to insuring a smooth-running experience with one of the most effective ways to remove contaminants from virtually any product that can be safely immersed in a water-based biodegradable cleaning solution or, with specially designed cleaners, volatile cleaning solvents.
This post looks at applying good safety practices dealing with
- The operator
- The ultrasonic cleaner
- Cleaning solution formulas
- Special safety features
- Equipment maintenance
Good Personal Safety Practices during Ultrasonic Cleaning
These are not overly complex. An important, if not the most important point to keep in mind is that ultrasonic cleaning solutions get hot due to cavitation action. Continuous operation can raise cleaning solution temperatures to 175⁰F or more - even with units not equipped with heaters.
Recommended cleaning solution temperatures are provided by the manufacturer, and a high temperature is not always desirable. Nevertheless you should never reach into an operating ultrasonic cleaner bath to remove and inspect parts. Not only do you risk burns, cavitation can penetrate your skin. Not a good thing.
The solution? Wear protective gloves before removing baskets containing the parts for inspection - the parts will be hot too!
Hearing protection may also apply to good personal safety practices. Although ultrasonic frequencies are defined as sound above the range of human hearing, audible sound is generated by the vibration of cleaning tank walls and other sources.
The potential for undesirable noise increases at lower cleaning frequencies such as 25 and 45 kHz. Over time this can be annoying to personnel.
The solution? Ear protection devices, cleaning tank covers or placing the ultrasonic cleaner in a sound-suppressing case.
Good Safe Operating Practices for the Ultrasonic Cleaner
You've made an investment in ultrasonic cleaning equipment. There are a number of steps you can take to safely operate this equipment and contribute to a long, satisfactory service life.
Provide a reliable source of power
Ultrasonic cleaners use powerful transducers to convert electrical energy to sound. Cleaners are supplied with a three-prong grounded outlet for their power source and must be connected to a similarly grounded outlet.
We also strongly suggest that the ultrasonic cleaner have its dedicated outlet, not an outlet or circuit sharing multiple high powered machines such as a sterilizer, autoclave or air compressor. Circuit overloads could cause a circuit outage, an unwelcome occurrence in any situation.
Safe Practices for Equipment
Other precautions can keep the equipment operating at peak efficiency.
One of those measures is that items should not be placed directly on the bottom of the tank, Ultrasonic vibrations that create the cavitation bubbles will also vibrate items in contact with the tank, eventually causing wear that can penetrate the tank bottom. This voids the manufacturer's warranty.
Instead, items should be placed in a mesh-bottom basket or tray suspended above the tank bottom. Note that some large industrial ultrasonic cleaners may be fabricated with ridges on the tank bottom to hold heavy parts. Alternatively, parts to be cleaned can be suspended from overhead racks to keep them from contacting the tank bottom.
Maintaining proper cleaning solution levels is also critical to ultrasonic equipment safety practices. These units are designed for a specific volume (level) of cleaning solution. In many units this is indicated by a fill line.
Evaporation and drag-out lowers the level. Manufacturers recommend that operators do not allow units to operate when the tank is less than 2/3 full. That's because a low liquid level can damage the generator and heaters within the equipment.
See our maintenance section below for additional suggestions.
Good Practices for Selecting Cleaning Solutions
Ultrasonic cleaners work at their best with a water-based, biodegradable detergent solution. Over the years a wide variety of ultrasonic cleaning solution formulations have come on the market. Most are shipped as concentrates; others are formulated to operate at full strength.
They are tailored to specific cleaning jobs ranging from cleaning grossly contaminated engine parts to medical and surgical instruments. iUltrasonic offers a menu of cleaning solution formulations along with advice on where they are best employed.
Volatile Cleaning Solvents .
Certain cleaning requirements may call for a volatile cleaning solvent such as IPA and acetone. In these instances special precautions apply to avoid a fire, explosion and health-related problems for personnel. For these applications an explosion-resistant or explosion-proof ultrasonic cleaner, together with code-required compliance concerning installation and operation.
If your cleaning operations require the use of flammable solvents call the iUltrasonic scientists at 973 440-2191 for advice and equipment recommendations.
Special Ultrasonic Cleaner Safety Precaution Features
Purchasing an ultrasonic cleaner equipped with a timer is strongly recommended. Some units show set and elapsed time, and will shut down at the end of the cycle. Others can operate continuously with an auto shut-down at 12 hours.
Models without an auto shut-down risk damage if users do not manually turn them off before leaving for the day or weekend. If this happens equipment is likely to burn out and/or damage parts left in the tank due to evaporation of the cleaning solution.
Ultrasonic cleaners that incorporate this safety shut-off feature include all Elmasonic E Plus, Elmasonic S, Elmasonic P, and Elma X-tra basic equipment available from iUltrasonic.
How Maintenance Contributes to Ultrasonic Cleaner Safety
Your instruction manual will have a section on tank maintenance.
The vibration created by ultrasonic transducers creates wear spots on the bottom of the tank that over time develop into abrasions termed cavitation erosion. This occurs even in tanks fabricated of cavitation-resistant stainless steel. This erosion will necessitate tank replacement before leaks develop.
You can prolong cleaning tank life by following these simple suggestions:
- When changing solutions flush out residues, especially metal particles and rust films that fall to the bottom of the tank during cleaning operations. These can serve as "drills" when vibrated by the transducer.
- Use the correct cleaning solution formulation. For example, do not use concentrated acids such as nitric, sulfuric, formic, or hydrofluoric acid directly in the ultrasonic tank. (Ask us about acid-resistant plastic inserts available as tank liners.)
- Drain cleaning solutions before they become too contaminated (and reduce cleaning efficiency). Clean the tank and fill it with a fresh solution.
- Turn your ultrasonic cleaner off when not in use.
We hope this information is useful in helping you to operate your ultrasonic cleaner in a safe manner.
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