Removing impurities from the process stream is crucial.
Pulp from cooking always contains some unwanted solid material. Some of the fibrous material may not be completely in the form of individual fibers. The main purpose of the pulp screening process is to separate harmful impurities from pulp with minimal fiber loss, and at an acceptable cost level.
Bark, sand, shives, and rocks are typically found within the cooked chips and must be removed. It is important for these impurities to be removed from the process stream as they can have negative effects on end product quality, may damage downstream process equipment, and may cause operational problems.