Water, as well as ultrasonic cleaning solutions, comes with dissolved air or gases.
And to enhance the cleaning results these trapped gases in liquid need to be removed before operating the device.
The process of removing the trapped gasses in the ultrasonic cleaner solution is known as ultrasonic degassing.
This is important due to the fact that gases are comparatively easier to compress.
And when the cavitation process starts in the ultrasonic cleaning system part of the cavitation energy is absorbed by these gases which goes waste without affecting the cleaning performance.
Degassing of the solution is also essential so that the trapped oxygen does not oxidize the parts that need cleaning, thereby providing the best overall performance.
Now that you know about what is degassing in ultrasonic cleaning, its important to know how it is done and how to tell whether the solution is degassed or not.
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How to Degas Ultrasonic Cleaning Solution?
Before you use water from your common pressurized water supply, it’s good to know that there are various dissolved gases and ions present in it naturally.
Tap water in general will contain dissolved oxygen, nitrogen, and carbon dioxide as the main gases. Few other less common are neon and argon.
The same holds true when you prepare the solution for your ultrasonic cleaning tank using this water.
It’s therefore good to learn how you can degas the solution for getting accurate cleaning results.
Degassing of the ultrasonic cleaning solution can be typically done by two methods:
1- Let It Sit
The first method is by simply letting the solution sit for a few hours so that the entrained gas settles down completely.
Have you wondered why a glass of water you take from the faucet to drink tastes differently than when you drink it after few hours?
The reason is you have allowed enough time for all the dissolved gases to sit.
Remember, when using this method, you are literally allowing the gases to sit and not remove.
Hence even in still water, the process of sonication will generate the air bubbles with gases filled in making the overall cleaning process imprecise.
2- Run the Ultrasonics
Secondly, you can degas the water and sonic solution by running the ultrasonic cleaner filled with a solution for 5 to 10 minutes.
Depending on the quantity and hardness of the sonic bath, it may sometimes take about 15 to 30 minutes to degas the bath.
Remember that you will need to run the machine with only liquid, without placing the elements to be cleaned.
The limitation of using this method is it can take longer if the tank is larger, like in models over 100 gallons.
To accelerate the degas process significantly you can either increase the temperature (if you have a heating option in the machine) or can operate the unit at higher frequencies (if you have a multi-frequency option).
Liquids tend to degas faster at higher frequencies and higher temperatures.
3- Use Machine with Degas Feature
While 5-10 minutes is shorter as compared to hours for sitting down the gases, you can still speed up the process by picking the cleaning system that has an inbuilt degassing feature.
The fast-degas feature that’s included in the machine will allow you to degas the liquid within a few seconds. And it’s done automatically each time you start the unit for cleaning the elements.
Ultrasonic cleaners with degas function are now available on the market that accelerates the process of removing the entrapped gases in the solution.
For industries that need to use the cleaning systems most often, these units are most preferred because they can deliver the most advanced and intensive cleaning without wasting any time.
Can You Degas the Water by Boiling?
Boiling water before using in the solution can degas it but its not much effective as it’s the water that has been degassed and not the complete solution.
When you boil and cool down the water, it will remove the dissolved gasses to a certain degree.
But when cooled in the open air, the gases (like oxygen, nitrogen, carbon dioxide, and others) can again enter the water making it less effective for use in an ultrasonic cleaner tank.
You will therefore need to cool it in a closed vessel, which is vacuumed.
How to Tell If the Solution Is Degassed Completely?
As we have seen, the solution needs to release the entrapped gases to get degassed.
So, as soon as you see the fine bubbles rising to the surface of the solution it means that the degassing process of the ultrasonic is started.
The process will last for few minutes to seconds depending on the method you choose from the above.
The degassing process comes to an end with a high-pitched sound from the ultrasonic tank which is clearly audible if you are near to the unit.
Plus, when the solution is degassed completely you will see no bubbles rising to the surface of the cleaner bath.
When degassing the solution for the ultrasonic cavitation process; remember that the solution once degassed does not need to be degassed again if you are using it multiple times for cleaning various elements.
You will need to de-gas the entrapped gases and bubbles from the fluid only when you are replacing it with a fresh batch of liquid in the tank.
Other than water, the degassing or deaeration is used in a variety of other higher viscosity liquids such as epoxies, silicone oils, motor oils, adhesives, beverages, paints, transformer oils, emulsion, polymers, inks, water-based aqueous solution, foaming liquids, candle waxes, resin aluminum alloy melts and many more.
Although continually replenished ultrasonic tanks do not need to be degassed, it’s important to degas the fresh solution every time you change it in the tank.
Ultrasonic cleaning machines that comes with in-built degassing capability can therefore save significant time and energy for larger projects.
But if you are using it for a smaller job, the complexity of the circuits and additional new controls you need to learn and manage should be taken into account.
If its worth your time and money – you should definitely go for it.