Voith, Germany, reports that the special structural features of its two new screen plates, NDuraPlate B and NDuraPlate D, achieve a higher pulping and screening efficiency of up to 30%. NDuraPlate D was specifically developed for machines utilizing flat screening plates for separation. With this screen plate, there is a lowered hole at the center of the overall pattern in addition to six conventional round holes. Due to the different height of the holes, the rotor, turning above the flat screen plate, creates micro-turbulences at the screen surface. This hydraulic action provides for a much improved way to keep the holes clean compared with standard screen plates and thus facilitates a throughput that is higher by up to 10%.

In place of the potential increase in machine throughput, the quality of the accepted fiber suspension can be improved by reducing the size of the hole, Voith says. Current hole size offering with NDuraPlate D is between 1.8 and 4.0 mm. In addition, the flake content can be reduced by up to 20%. The clearly improved quality of the accepts unburdens the downstream process stages and reduces fiber loss.

With NDuraPlate B for pulpers, both the productivity as well as the quality of the pulp suspension is increased. The longer working edges of the new bean-shaped hole design bring about a gentle fiber pulping. They allow substantially higher pulping and energy efficiency than a conventional hole screen plate. The specific energy consumption drops by up to 15% with use of the new screen plate. In addition, better deflaking is possible by around 30%, according to Voith.

More information is available online for NDuraplate B and NDuraplate D.