What is ultrasonic degassing? How to degas ultrasonic cleaning tanks

What is degassing? For ultrasonic cleaning equipment, degassing is the process of removing dissolved gases, such as air, from the liquid cleaning solution before the cleaning cycle begins. Proper degassing helps the ultrasonic tank produce stronger and more consistent cavitation because trapped gases can absorb ultrasonic energy and reduce cleaning performance. In simple terms, degassing prepares the solution so the ultrasonic cleaner can clean parts more effectively from the start of the cycle.

Degassing is important because ultrasonic cleaning depends on cavitation, the formation and collapse of microscopic bubbles that provide the cleaning action. When excess air or gas remains in the solution, it cushions the cavitation energy and makes the ultrasonic tank less effective. Removing dissolved gases allows more ultrasonic energy to reach the parts being cleaned, which can improve cleaning consistency, especially in precision cleaning applications.

Any water that comes from a pressurized water supply will naturally contain dissolved gases, and therefore the water will need to be degassed when first dispensed. The degassing process ensures that the ultrasonic cleaner operates at peak efficiency from the start of the cleaning cycle.

In most ultrasonic cleaning tanks, degassing is mainly required when new solution is added, when the tank is freshly filled, or when solution has been transferred from a pressurized source. Once the solution has been properly degassed, it usually does not need to be degassed again unless new liquid is introduced or the tank chemistry is replaced.

Options to degas ultrasonic cleaning tanks

• Let it sit – Degassing solution is easily achieved by letting the solution sit out for a number of hours. This is why a glass of water tastes “different” when first out of the faucet vs. drinking it hours later.

• Let it run – Run the ultrasonics just as you would ordinarily, but without the parts to be cleaned. Running the ultrasonics will accelerate degassing significantly, typically reducing the process to about 5–10 minutes. Keep in mind that the cleaning solution usually only needs to be degassed when it is first dispensed from a pressurized supply or when new solution is added to the tank.

• Fast degas ultrasonic cleaning system – Although 5–10 minutes is much shorter than hours, it may still be too long for production parts cleaning systems that refill or transfer solution before a cleaning cycle. A fast-degas feature supports rapid degassing at the start of the ultrasonic cycle, helping the tank reach effective cavitation faster and reducing waiting time before parts are cleaned.

The fast-degas feature can be heard in the video below. Note the high pitch of ultrasonic degassing and tuning amplified for demonstration.

How to tell if a solution is degassed or not?

The cleaning solution de-gases simply by releasing the dissolved and entrapped air in the solution. During a degas process with ultrasonics, fine bubbles will suddenly appear and begin to rise to the surface of the solution (similar to that seen after first pouring a glass of beer). This implosion or cavitation of the solution with dissolved gases can result in a high-pitched audible sound from the ultrasonic tank until the solution is degassed as heard in the video above.

Once a solution or fluid is degassed either by letting it sit, ultrasonic cavitation energy, or heating, it does not need to be degassed again unless the solution replaced with new fluid.