Air sparging is a popular method of tank agitation commonly used throughout the cleaning industry. This technique involves pumping air through the cleaning tank, often through a pipe with holes drilled for bubbles to escape.
While the idea is to promote more fluid movement, which improves cleaning solutions ability to remove debris and grime from parts and reduce cleaning times, Brulin has long advocated against using air sparging in precision cleaning applications.
In a 2017 white paper, Brulin researchers talked about the issues air sparging can introduce, which are highly problematic for a precision cleaning process.
- Air sparging introduces CO2 into the tank, which causes carbonic acid to form. Carbonic acid reduces the cleaning solution’s bath life by neutralizing the alkalinity and which can lessen its material compatibility qualities.
- Sparging also introduces oxygen, increasing the risk of oxidation corrosion of steel components.
- Oils can enter the tank either through the compressor or the atmosphere.
- Air sparging may cause excessive foaming with some soak-tank degreasers. This excessive foam will then contaminate your rinse as it is carried over with the components and baskets.
And perhaps most importantly, air induced agitation is not an effective method of agitation to achieve thorough tank mixing which may lead to hot or cold areas in large tanks.
Any of the above issues could spell significant, if not process-stopping, trouble in precision cleaning. What should precision cleaning processes turn to for tank agitation? We recommend under-surface turbulation.
What is Under Surface Turbulation?
Proper tank agitation is critical to achieving a superior clean. The movement of the detergent created by the agitation ensures that the solution both contacts the soil and has the movement to remove it from the part surface.
Brulin experts strongly discourage using any process that introduces air into the cleaning tank, as the issues above are likely to occur. Instead, use eductors to introduce turbulent movement of the cleaning solution within the tank and against the part without agitating the surface where the solution and air meet.
In plain English, the tank's surface will appear pretty calm, but below, the detergent is being circulated quite violently. This also keeps soils from accumulating on the bottom of the tank and sweeping them toward the tank’s filters, increasing bath life and reducing maintenance needs.
Brulin researchers found that with an agitation rate equivalent to 50X turnover/hour, a manufacturer may expect the required time to remove the surface contamination to be reduced by about 33%. Parts with blind holes utilizing directed eductor solution agitation may also expect a significant reduction in cleaning time of up to 50%.
Other Tank Agitation Methods
While Brulin strongly recommends the use of under-surface turbulation due to its low cost, other effective methods exist that are superior to air sparging, such as:
- Ultrasonics: Sound waves are used, which create tiny bubbles that form and violently implode, scrubbing debris away. However, it is most effective in smaller tanks due to high equipment costs.
- Stroke: Use of up and down movement of the parts within the tank solution
- Tumbling: Use of rotation within the tank solution and is often combined with a stroke movement to enhance cleaning.
- Recirculation: Pumping of the solution from one end of the tank to the other to create a constant, usually low-speed, fluid flow.
- Agitator: Cleaning solution movement within the tank is accomplished using a propeller or other turbine agitator.
While ultrasonic agitation is also a preferred method, high equipment costs make adoption difficult. Our research indicates that under-surface turbulation is the most cost-effective and accessible agitation method that most customers can implement quickly and affordably.
How Brulin Can Help
In addition to having more than eight decades of experience in cleaning chemistries, Brulin’s experts have extensive experience in helping our clients achieve better process efficiencies, such as moving away from air sparging in favor of better and more effective tank agitation methods.
We can help you learn how to improve your precision cleaning processes. Request a free Brulin Process Audit of your current system today to match the correct cleaning chemistry to the needs of your process.
