15. April 2020
The bar for energy conservation and productivity is high at Nestler: With an optimized steam system, the 120-meter-long BHS corrugated board plant works with steam pressure reduced to 0.5 bar – minimum values for the industry typically lie between two and three bar. As a result, the specific energy consumption has already been reduced by ten percent, which is also reflected in glue consumption that has been cut by eight percent. The 16-meter-long heating and traction section is equipped with 18 heating plates and works with a plate-roll clamping system. Depending on the product mix, the heating belt transports an average of 30,000 square meters per hour and is exposed to a maximum steam pressure of up to 16 bar and surface weights of up to 1,400 grams.
In order to further optimize energy consumption, the corrugated board manufacturer switched from its conventional belt in 2015 to the CONDUCTO© 3313, which GKD had just launched. Its construction from polyester monofilaments with bronze wires interwoven in the running direction and an aramide reinforcement in the edge area is significantly lighter in comparison with other products on the market used by Nestler. Thanks to special thermosetting, it is also permanently dimensionally stable, which qualified it for Nestler’s demanding requirements for dimensional and tracking stability. Its open mesh structure ensures immediate full-surface moisture evaporation of the corrugated board, enabling faster drying and better flatness of the products. With 180 million running meters in three years without a single downtime caused by the belt, the CONDUCTO© 3313 also showed what it can do at Nestler in terms of long-term performance. “The previous belt lasted for a maximum of two years,” says Eva Labusga, Head of CBP, Planning, and Production Control at Nestler. Although the belt was still fully functional after three years, the corrugated board manufacturer changed the heating belt again after three years in order to test the improved belt design with the CONDUCTO© 3322. The prospect of improved grip – the CONDUCTO© 3313 first needed to be ground – and the expectations of less running noise directly after mounting spoke in favor of this new trial from the outset. The CONDUCTO© 3322 is a hybrid mesh made from an internal structure of polyester monofilaments and staple fibers with bronze wires inserted in the running direction and a warp made of staple fiber yarn. Like the predecessor model, its edge is reinforced with aramide. Due to the textile material in the CONDUCTO© 3322, the grip is very good right from the start and the running noise is quieter than with the CONDUCTO© 3313.
All in all, Nestler was impressed by both belts: Neither of them has a tendency to clog and the self-cleaning CONDUCTO© 3313 didn’t even exhibit any soiling through superficial adhesions of paper and glue. In addition, both belts are significantly thinner than conventional belts: At 4.6 millimeters, the CONDUCTO© 3313 is 1.1 millimeters thinner than the CONDUCTO© 3322. The lower weight makes mounting much easier: The belts can be changed within three to four hours, which Eva Labusga claims is half the time required for conventional models. Plus, the belts enabled Nestler to reduce drive energy consumption as they had wanted: Both belts produced energy savings of 15 percent compared to the belt used previously. In Nestler’s opinion though, the biggest advantage of both belts is their high air permeability, which enables fast, even moisture evaporation from the board. In addition to quality improvements in processing and the end product, the significantly faster drying and better flatness of the board generated an eight percent increase in process speed at Nestler.