PROCESSWEST Magazine Online

Liquid Filtration System Cleans up Soap Production

Don Horne   



While maybe not quite as frightening as the famous Alfred Hitchcock shower scene, just imagine the shock of stepping into a hot shower, unwrapping your favorite bar of soap, and discovering that it’s already dirty. It can happen.

That’s because soap contains glycerin, which brings with it important moisturizing properties. During the manufacturing process, glycerin is heated and added to the soap formulation before it goes to final production.

However, the heating needs to be precise with little margin for error. When it is not heated properly, the soap can turn brown and even form brown specks that are small but still very much noticeable, hardly the 99 and 44/100% pure that a good soap needs to be.



For one of the world’s largest suppliers of bar, detergent and body soaps, meeting that lofty goal is imperative to success. Supplying virtually every type of soap made, the company on any given day will see some 25 different brands of soap rolling down its production line. With multiple brands and products at stake, and high quality standards to live up to, the company was more focused than ever on creating an efficient production process.

Relying on an outdated heating and filtering process, the company often had to reroute soap back into the assembly line to remove the brown haze and specks caused by the improperly heated glycerin to ensure that quality objectives were always achieved. The rerouting was necessary, but was inefficient, expensive and time-consuming. Additional labor was also required resulting in added labor costs and significant down-time. It was time for the company to take a closer look at its filtration system as part of streamlining manufacturing operations.

Many manufacturers consider upgrading existing filtration systems or adding new filtration systems an unnecessary expense. This is understandable, since the solids in process fluids only occasionally cause catastrophic failures, and in this case, time consuming inefficiencies. However, the hidden costs created by contaminants are significant, while the cost to filter and remove them is modest and can be recovered quickly. With the proper systems in place, significant benefits can be achieved.

Selecting filtration equipment is the combined result of many considerations. In addition to removing undesirable material from a liquid stream, the filtration method selected must also satisfy other requirements. Installed costs must be weighed against operating costs. Waste disposal costs must be considered. Is continuous flow a requirement of the application, or can the filtration equipment be operated intermittently? Is worker exposure to the process liquid during filter cleaning or replacement a problem? These and other factors were considered by the company when choosing a new filtration method for their operations.


While the final product was eventually meeting purity goals, the soap giant very much wanted to clean up the process. In doing so, they turned to Eaton’s Filtration Division and installed a DCF-800 automatic self-cleaning filter for a 90-day trial run. It performs a self-cleaning action by mechanically scraping collected debris from the filter screen with a disc that moves up and down the screen, parallel to the liquid flow. Collected debris is then automatically purged from the collection chamber at the bottom of the filter. This self-cleaning action is performed without halting production and provides the highest quality filtering under continuous demand. Because the screen is cleaned continuously, a consistently high flow rate is maintained.

Uninterrupted filtering by the DCF-800 filter also helps ensure consistent temperatures, a feature essential to meeting quality objectives.


Before the 90-day test was even completed, the soap company was already washing its hands of the brown mess and has since ordered two new DCF-800 filters. “Removal of the glycerin impurities was very successful,” reports Bruce Law, regional sales manager for Eaton’s Filtration Division. “The test unit delivered everything that we said it would.”

As the trial demonstrated, careful consideration and testing when choosing a liquid filtration system will offer numerous potential benefits. A wise filter selection can minimize process downtime, reduce waste disposal costs, limit worker exposure to the process liquid, reduce maintenance time and expense, and improve product quality. Therefore, it is important to review all the available filtration options and identify potential areas where adding or upgrading filtration can provide cost savings.

As a result of testing this new approach, Law believes the costly rerouting of soap will soon be virtually eliminated. “It’s still too early to gather a measurable return on investment,” adds Law, “but based on the results of the trial, the number of bars of soap that the company produces, and the cost to rework an out of spec product, it strikes me that the payback is going to be pretty quick.”


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