Emerson density meter transforms Italian paper mill operations 01 July 2011

The Cartiere del Garda paper mill, on the banks of Lake Garda in Italy, is reporting reduced costs, improved quality and less waste since commissioning a high accuracy density meter, from Emerson Process Management.

Fulvio Prati, instrument manager at Cartiere del Garda, explains that the plant installed a Micro Motion 7845 density meter to monitor the concentration of kaolin and other additives in the coating process in entrained gas conditions.

"The highly accurate measurement of the coating mixture concentration means we have been able to discontinue the use of expensive additives," he says "This has enabled significant annual savings and paper quality has also been improved."

Cartiere del Garda operates one of the most modern paper mills in Italy, specialising in high quality coated papers. For many years, a Micro Motion Coriolis flowmeter has been used to monitor the concentration of the paper coating mixture. However, because the recirculation system on the feed tank generated entrained air, expensive additives were required to prevent quality problems.

The existing Coriolis flowmeter was not designed to provide the required degree of density measurement accuracy under entrained air conditions – and hence the new on-line instrument, which measures solids concentration of the coating solution directly at the film coater machine feed to +/-1%.

In fact, the device selected measures density in aerated liquids to better than +/- 0.5% with very high stability and repeatability, providing a 4—20 mA signal to the control system, related to line density, which is in turn converted into percentage solids.

Interestingly, the device is a straight tube, liquid density meter that uses a vibrating tube to measure density. As liquid density changes, it affects the vibrating mass of the tube, which affects the resonant frequency to an extent that is inversely proportional to the density of the process fluid. By monitoring that frequency and applying standard conversions, the instrument provides in-line density data.

Brian Tinham

Related Companies
Emerson Process Management

This material is protected by MA Business copyright
See Terms and Conditions.
One-off usage is permitted but bulk copying is not.
For multiple copies contact the sales team.