The PFI mill is used for beating laboratory-scale pulp samples. Correct beating is the first important step in preparation of hand sheets of the required quality. The core of the PFI mill are the inner toothed beater unit with its 33 blades and an outer smooth beater housing. The beater unit and housing rotate in the same direction at different peripheral speeds. A beating force of exactly 3.33 N/mm ensures that the pulp is beaten under standardized conditions.
A weighed pulp sample prepared with a standardized disintegrator is added to the pulp container and spread evenly across the entire inner wall. Then the beater unit is lowered into the housing. When the start buttons are pressed, the beater housing starts rotating and the beating process commences. The mill stops when the preset number of rotations is reached. The beaten pulp can be removed and the Schopper-Riegler value determined, where required. The mill is ready for further beatings, so that a beating curve can be created.