Contract pilot coater offers optimized system.

When Western Michigan University (WMU), Kalamazoo, Michigan, USA prepared to open its new contract pilot plant facility for paper coating, it wanted to enhance operational capability, flexibility, and maintenance. The goal was to more effectively approximate the production runs for paper mills and paper suppliers wanting to improve current products, develop new products, or try new coating methods or equipment.

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The coating plant and its sister plants on the WMU campus provide strategic research and development resources for the paper and printing industries. Ninety percent of the plant activities at WMU--including coating, papermaking, printing, and recycling--support their operating budget through contract services with the paper and printing industries.

The new contract pilot coating facility at WMU has particular importance to the paper industry, since only four facilities are commercially available in North America. The unit is the only pilot coater in North America not owned by a coating materials supplier. This is a strategic benefit to companies seeking objective coating research and development on a confidential basis or to those who lack appropriate in-house resources.

"Our job is to supply industry with as near to actual production conditions and equipment as possible," said Jan Walter, general manager of pilot plants at WMU. "When running on a pilot coater, chemical suppliers are not only looking for the finished performance of their coated paper but also monitoring the runnability of the coating. We never know what type of coating will be run, what materials will be used, or the quality of the base paper. Because we run several test conditions a day, we have to clean the supply system frequently to ready it for the next coating."

Due to the variety of coatings and papers involved, proper process filtering of the type found in actual paper mills was a critical part of enhancing the new operational capability of the coating plant. WMU selected Ronningen-Petter, a RPA Process Technologies brand, for an effective process filtration solution.

RPA Process reviewed the coating pilot plant installation at WMU and noticed different flow rate needs depending on the setup configuration of the coater. Since the pilot plant might use one coating or two different coatings, the facility has a system used in mill metering size press installations and applications where similar setup needs exist.

Two Ronningen-Petter Disc Cleaned Filter (DCF) stations now share the same drain lines and inlet-outlet headers at the coating pilot plant. They are between the run tanks and the coater.

With the DCF mechanically cleaned filter, coating enters the top inlet of the filter housing and passes through the screen. The screen holds any particles over 75 microns. Cleaned coating exits the bottom outlet of the filter. A cleaning disc moves up and down the filter screen to remove debris. With the downward fluid flow and the disc movement, the debris deposits into a holding chamber at the bottom of the filter housing for regular purging from the housing via a valve.

"We monitor the differential pressure of the DCF filter to see if the cleaning system is being over-tasked by a high debris level in the coating," said Walter. "So far, we have not found a coating or dirty basestock it could not handle. The differential pressure remains steady. Its ability to remove air from a coating is also a great asset for runnability, especially when we are operating the short dwell applicators.

"The filter is very easy to clean, and we have not had to open it to remove coating," continues Walter. "We simply flush the system with water. We have no compatibility problems."

For more information, contact RPA Process Technologies, Inc., 9151 Shaver Road, Portage, MI 49024-6798. In North America, call 1-866-867-2893 or fax [phone]. Information is also available at www.rpaprocess.com.