The new OptiFlo headbox family brings together our unrivaled expertise and new technology, opening the door to improved quality and increased productivity in all forming applications. Valmet's cost-effective two-layer headbox makes it possible to produce lightweight containerboard with only one hybrid forming unit or with Fourdrinier type former.
OptiFlo Layering Fourdrinier tackles the board makers’ challenges in combining lower basis weights, faster speeds and higher ash contents resulting from the increased use of recycled fiber. OptiFlo Layering headbox enables feeding different stock into each layer, which in turn means that the structure of board can be further optimized.
Having two separate headboxes is a much bigger investment compared to a layering headbox. But the cost savings do not come only from the initial headbox investment. There are possibilities for great operational cost savings as well. With two headboxes you have two wires running with all the water and chemicals. These require cleaning and changing wires, which take a lot of time. All of these create a higher operational cost compared to a layering headbox. So, it is not only about the initial headbox investment, but consider also the cost savings in energy, chemicals and consumables.
In two-layer headbox applications, it is very important to guarantee layer coverage. All hydraulic components of the OptiFlo Layering Fourdinier headbox have been designed to minimize slice jet and board sheet disturbances. This novel solution provides excellent layer coverage, considerably lower residual variation in basis weight as well as an excellent formation with no streaks or tiger stripes. The OptiFlo Layering headbox hydraulics’ design produces smooth forming board activity, without any mixing of individual layers.
Valmet's latest innovation, aqua layering technology uses a thin water layer as a headbox wedge to stabilize layers and to form an even film while layers of stratified paper are being joined together.
It prevents the mixing of stock layers and also enables the feeding of functional additives between the stock layers. Read more about the benefits of aqua layering here.
Valmet’s unique three-layer headbox was at the heart of Sappi Maastricht’s rebuild where the aim was to improve board properties and quality. The old headbox was replaced with completely new type of headbox, supplying three simultaneous layers of stock, leaving forming and the press section unchanged. “Having three separate headboxes would have been a much bigger investment – ten times what we needed for this machine,” says de Koning. There are other benefits, too. Not all the grades produced in Maastricht (graphical, SBS, FBB) are traditionally layered, but the mill has found it valuable to layer all their grades. They optimize the quality and cost of each layer for each grade.
Watch the video and learn how Sappi Maastricht managed to get into the specialty boards business with a unique three-layer headbox, producing extremely high-quality SBS and FBB with superior smoothness and printability.
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