PRETREATMENT, SURFACE PREPARATION, DEGREASING & CLEANING Cleaning of industrial pre-treatment liquids with centrifuges Achieving substantial annual cost savings and improving sustainability

Goals like sustainability and saving valuable resources are increasingly becoming competitive factors across practically all industries. When it comes to cleaning a variety of industrial processing liquids, the cleaning centrifuges from Rösler offer a substantial potential for reaching these goals. Along with significant savings in the use of chemicals, they help reduce the consumption of water by up to 90 %. With these benefits the Dutch company Ulamo, specialised in powder coatings, could not only make a contribution towards environmental protection but was also able to reduce the annual costs for pretreatment by thousands of Euros.

Over the past 60 years Ulamo has grown to become a provider of complete coating solutions and today is a leading supplier for the manufacturers of radiators. The company, located in Ulft, Netherlands, offers powder coatings to customers all over Europe for various products made from aluminium and different steel grades. Ulamo also produces decorative radiator panels, which the company sells to its customers under the trade name “Sentimo”.

Problems with the pre-treatment liquids

Before they can be powder-coated, the components must generally be de-greased and undergo a “wet” chemical cleaning process in the form of a spraying operation. The cleaning liquid, contaminated with dust and grease, is collected in a special tank. To maintain the cleaning characteristics of the liquid and re-use it, certain chemicals have to be added. The downside of this approach is that the degree of contamination is rapidly increasing. To partially offset the progressive contamination, the amount of added chemicals has to be continually raised. In addition, the dirt contained in the liquid migrates into the spray nozzles and, subsequently, is passed onto the components. This created numerous problems:

Plugged up nozzles prevent the cleaning liquid from reaching all surface areas of the components, resulting in a highly erratic pretreatment.

Therefore, frequent controls of the nozzles and their exchange are becoming indispensable. This causes frequent interruptions of production and high labour costs.

Moreover, the liquids must be regularly replaced and cleaned, which is also costly and disturbs the production flow. In addition, the discharge of the tanks and refilling them is an environmental hazard.

Simon Wagenaar, manager of the technical services department for coating at Ulamo Coating BV explains: “The contamination of the cleaning liquids was costing us thousands of Euros for personnel, lost sales and scrap parts.”

Cleaning centrifuge eliminates the problems

It is not surprising that Ulamo was looking for a solution to this problem and finally found one at the Dutch subsidiary of Rösler. The solution consists of a cleaning centrifuge: A charging pump transfers the liquid from the tank into the rotary basket of the centrifuge. The high centrifugal force of the rotary basket causes the tiny dirt fines to be deposited on the basket wall in the form of sludge. The liquid, now free of the contaminants, is transferred back into the cleaning process. Simon Wagenaar continues: “Any investment in new equipment should amortise itself relatively quickly. Therefore, it is always good to learn that an investment really pays for itself. Rösler allowed us to test the centrifuge free of charge for a month. So, we only had to commit to a purchase after we had learned that our requirements can be met. For my department, where we are coating aluminium components, we installed a semi-automatic centrifuge.”

A second centrifuge for coating of steel components

Later on, for the coating of steel components, primarily radiator components, the company purchased a second cleaning centrifuge. Norbert Becking, production manager for coating at Ulamo Metaal B.V., adds: “Once we saw how well the centrifuge technology works, we purchased a fully automatic centrifuge for my department. We had previously tested a unit from another supplier. But this was too big and complex.”