At a high tech paper mill on the banks of Lake Garda in Italy, real-time measurement of kaolin and other additives in the paper-coating process resulted in direct savings for the company.

Cartiere del Garda ( www.gardacartiere.it) specializes in high-quality coated papers. According to Instrument Manager Fulvio Prati, for many years a Micro Motion Coriolis flowmeter from Austin, Tex. automation supplier Emerson Process Management ( www.emersonprocess.com) reliably and accurately monitored the concentration of the paper coating mixture. However, because the recirculation system on the feeding tank generated entrained air, it was necessary to add expensive additives to the coating mixture.

Removing the additives would reduce production costs, but would cause up to 20 percent air to be entrained in the coating mixture. Since the existing Coriolis flowmeter was not designed to provide the same degree of density measurement accuracy under these conditions, Cartiere del Garda sought an alternative. What they chose was an on-line, solids concentration measurement of the coating solution, made directly at the film coater machine feed.

A minimum accuracy of +/-1 percent of solids was required, said Prati. A Micro Motion 7845 straight tube, liquid density meter now provides highly accurate density measurements under entrained gas conditions. It delivers accuracy of better than +/- 0.5 percent with very high stability and repeatability, said Prati.

“The highly accurate measurement of the coating mixture concentration… means we have been able to discontinue the use of expensive additives,” said Prati. “This has enabled significant annual savings, and paper quality is improved.”

Cartiere del Garda ( www.gardacartiere.it)
Emerson Process Management ( www.emersonprocess.com)

Renee Robbins Bassett , rbassett@automationworld.com, is Manager Editor of Automation World .