A proprietary water cooling technology improves the calendering results compared to usual paper production conditions. Papermaker Stora Enso is putting the Valmet technology to the test at its BM 4 packaging board machine in Ingerois, Finland. The rebuild is expected to improve board quality and bulk saving potential. The rebuild includes web moisturizing and evaporation cooling equipment dubbed aqua cooling.

Valmet notes that the best calendering results are achieved when the web is cool and stiff, like in pilot trials for example. With Valmet’s aqua cooling technology, the pilot-type environment is brought to production level by cooling the web before the calendering nip. This is enabled by applying a small amount of water with a moisturizer and evaporating it with an air dryer.

According to Valmet, aqua cooling calendering is intended to make the end-product more lightweight without compromising functional and visual properties. Valmet has a pilot machine with aqua cooling technology available for customer trials.