All the instrumentation and controls are located in a cabinet by the coater at the Sappi Alfeld mill.
Sappi Alfeld in Germany is among the first to use Valmet’s latest coating station member in the new OptiCoat family. With the improved OptiCoat Jet blade coating head, Alfeld has been able to further improve coating profiles and to make coating head maintenance easier. The most recent safety regulations are also taken into account with as little interference with operations as possible. One thing stands out: “Our customers are really happy with our products,” says Sappi Alfeld’s mill director Stefan Karrer.
At the Sappi Alfeld mill, the product range is wide. The amount of design coating color varies from as low as 2–14 g/m2. Stefan Karrer is happy about the state-of-the-art jet application method and its coating possibilities: “In bent blade mode, the coating station provides the highest coating grammages, but it’s also possible to apply thin coating layers,” he says.
For the mill, the application method and cross direction control capabilities are important for uniform application and excellent CD profiles. One of the most interesting features to improve profiles is the new blade holder. This might sound like a technical feature too insignificant to mention, but it is actually one of the key factors in achieving consistently excellent profiles. Deposits of coating on the blade guiding surfaces are known to deteriorate the coating profiles. The new design of the blade holder makes it easier for the operator to keep the critical surfaces clean during everyday production. The ingenious clamping mechanism is also virtually maintenance free.
New type of blade holder provides consistently excellent profiles
The new generation of OptiCoat Jet blade coating head combines the proven features of earlier versions of OptiCoat Jet and ValCoat Jet with new enhancements. It provides very uniform coating quality. The basic coating method has remained the same: A surplus coating layer is applied to the paperboard surface with a jet nozzle. The excess coating is doctored by metering blade and returned back to the machine tank. The desired coatweight is achieved by adjusting the angle or pressure of the blade.
The instrumentation in Valmet’s coating stations has always been well thought out and protected from coating splashes. The positive feedback from paper mill maintenance professionals has also encouraged Valmet’s development engineers to take accessibility to a new level. The instrumentation and controls are now located right next to the coating station in a cabinet with doors that open on three sides. Accessing service items has never been this easy or quick before.
In an industrial environment, the importance of safety is ever increasing. No matter the safety regulations and laws, ease of operation should not be affected. The user’s point of view has been central in designing the unique safety features. The opening safety fence is one good example of a simple aid to maintaining the machine.
Opening safety fence for easy cleaning.
Overall, the goal with all coating processes is to achieve the desired surface characteristics with uncompromising uniformity—day in, day out. The OptiCoat Jet blade coating station provides excellent, easily adjustable profiles in a safe, easy-to-maintain operating environment. Sappi Alfeld and its customers get what they want: excellent, uniform quality.