Effect of Initial Dewatering Layout of a Gap Former on Sheet Structure and Printability, PaperCon 2010 Conference

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The main focus of this paper was to study the impact of three different types of gap formers on formation nature and further on the properties of printability.

Two of the tested forming sections were roll and blade type gap formers and the third one a novel shoe and blade type gap former. The three tested gap formers differ from each other with regard to the way the initial dewatering takes place, i.e. initial dewatering speed (gap pressure) and time delay between the initial dewatering and the loadable blade section dewatering.

The discussed forming techniques were operated on a pilot scale under similar conditions which corresponded to a production scale paper machine. The influence of forming mechanisms on sheet structure was studied by using a z-direction sheet splitting method. The printability of differently formed papers was studied with a commercial scale print press.