During the pulping process, a predefined mixture of recovered paper is broken down roughly using water and mechanical energy. The roughest impurities are then removed from the resulting pulp with the aid of a wire sieve. Afterwards it is put through a screening drum and undergoes coarse and fine screening. So-called reject pulp is the waste material separated by the various screening processes.
The headbox evenly distributes the pulp slurry on a moving sieve or “wire”. Water is removed from the pulp by drainage foils and vacuum. The paper web enters the pressing section of the machine with a solid content of about 20%. By applying hydraulic pressure, the solid content of the sheet is reduced to approximately 50%. The high-pressure shue press increases the solid content to 55%. In the following drying section, running the paper web over cylinders heated to approximately 140 °C further reduces the moisture content. In the subsequent size press, sizing, that is, starch or glue, is applied to the surface. This allows specific surface and strength characteristics of the paper to be improved. Starch is applied to one or bothsides of the paper. Sizing adds moisture to the paper which is removed in the after-drying section, resulting in 7-9% moisture content. The paper machine is controlled by personnel in the control room on site with the aid of the most modern process control systems.
At the end of the paper machine, the sheet is wound onto a jumbo-reel. The reel is then mounted in the rewinder where knives are used to cut the sheet into rolls of the desired width and diameter. Upon completion, according to the customers’ requests, the rolls are fitted with sleeves, plastic strapping and labels. A conveyor belt transports the finished rolls to the warehouse, where they are stored until the order is called.