Ultrasonic cleaners use sound waves and the cavitation effect of rapidly collapsing bubbles in a liquid bath to thoroughly clean objects placed in them. While ultrasound and the cavitation bubbles it produces will produce a cleaning effect by themselves, they are most effective when used in conjunction with a cleaning solution added to the water bath.
What is an Ultrasonic Cleaning Solution?
An ultrasonic cleaning solution involves the combination of ingredients put together in such a way to bring about the desired type of cleaning reaction. Ideally, an ultrasonic cleaning solution, or detergent, should contain ingredients that lower the surface tension of the liquid. This has the effect of increasing cavitation in the liquid as ultrasonic waves pass through it, thereby multiplying the cleaning effect, overall.
Cleaning Solution Types
Cleaning solutions and detergents vary in formula composition depending on what sort of object is meant to be cleaned and the material of which it’s made. There are general use soap solutions, descalers for cleaning rust or mineral deposits, enzyme solutions for removing heavy grime, low pH cleaners for brass, and many other specialty detergents.
Cleaning Solutions Are Green
Unlike harsh chemical solvents, which must be disposed of and/or stored with care, since they pose a real danger of contaminating the environment, ultrasonic cleaning solutions are much greener. These detergent solutions are usually made from ingredients that are easily broken down and/or disposed of without harm to the environment. They can be safely stored without much need for safety precautions and can be handled without extensive safety equipment.
Reusing Cleaning Solutions
Another advantage of ultrasonic cleaning solutions is the ability for many of them to be used and reused in industrial cleaning applications. Their longevity lowers operating costs for ultrasonic cleaning, overall. Best practice for reuse of ultrasonic cleaning detergents involves installing specialized filters in the ultrasonic cleaning device to catch particles and debris and/or separate oils and contaminants out from the detergent. With the filter in place, the detergent can be drained back out of the machine after use and reused until the detergent itself begins to break down and lose effectiveness. Actual longevity of the detergent solution itself depends on the type–manufacturer’s recommendations should be followed in this case.
Disposing of Cleaning Solutions
Once the ultrasonic cleaning solution is exhausted, it must be disposed of. Although ultrasonic cleaning solutions are much greener than industrial solvents, they must be handled in a similar way to other household detergents and should not be simply introduced directly into the wastewater disposal system. Most companies store used detergent in drums to be collected by a waste management company and disposed of properly. Since the detergent solution is about 95% water or higher, this disposal should be simple and inexpensive.
Heat and Ultrasonic Cleaning Solutions
Besides the power of cavitation and the accompanying detergent, effective ultrasonic cleaning may also rely on the introduction of heat to the liquid bath. Heat has the effect of efficiently eliminating trapped air in the liquid bath, increasing the effectiveness of cavitation. A temperature of 122-149 °F (50-65 °C) is optimal for most industrial cleaning applications. However, for some medical cleaning applications, temperatures below 100 °F (38 °C) may be required in order to prevent protein coagulation.