Cement Energy & Environment

34 KHD continuously improved its roller presses with the following mechanical features to enhance their reliability and performance: • use of multi-row cylindrical roller bearings • exterior roller guide to allow skewing without material stress • roller surface design with welded or ground profiles, or advanced stud lining • optimized hydraulic system • simple but effective feeding device • special frame structure • intelligent machine design that ensures easy access and exchange of the rolls Roller surfaces require continuous attention to ensure best grinding performance, wear life and nipping properties. As a result, the roller surface has received a variety of improvements and developments over the years. Today, KHD offers the following surface options: Complete hard facing “CHF” (Complete Hard Facing) has proven successful over decades and is widely used. This surface type offers the balance between low investment and wear life. Although the surface requires maintenance intervals for rewelding, this can be executed quickly during regular stoppages. CHF (Fig-3) combines a base material, different buffer layers and the multi-layered hard facing. Depending on specific requirement, the hard facing can be shaped with any possible profile type to improve the nipping characteristics that best suit the feed material. Stud lining Stud lining (Fig-4) offers best-in-class wear protection and outstanding performance. Firstly, the used tungsten carbide studs are extremely wear-resistant thanks to a hardness of 65 to 67 Rockwell. Secondly, due to the stud arrangement, an additional wear protection layer is formed from ground material that remains between the studs during regular grinding. And thirdly, studs also offer superior nipping properties as well as the use of thicker slabs. This allows an increased throughput rate. High-chrome KHD’s newest surface option is a special compound casting bandage (HCB) with a wear-resistant top layer made of high-chrome (Fig-5). This surface combines robustness with ease of use because it does not need to be rewelded. In comparison to competitor solutions, KHD’s profile application method is also advanced. Because we grind the profile into the surface instead of welding extra material on it, we prevent tiny surface cracks, that can lead to major follow-up problems during regular operation. Fig-3: CHF surface Fig-4: Stud lined surface Fig-5: High Chrome bandage surface