Broke Cleaning and Screening

"Broke" refers to partly or fully manufactured paper or board that is discarded from paper or board making, converting, and finishing processes. It also refers to the stock made by repulping these materials. Broke is continuously being produced and it is the job of the "broke system" to collect this valuable resource and supply it back to the paper or board making process for reuse. Many broke systems include cleaning and screening stages just before the broke fiber is returned to the machine furnish. The purpose of broke cleaning and screening systems is to remove contaminants from the broke stream, break apart fiber flakes and bundles in the broke to improve sheet uniformity and minimize fiber losses, and return a clean, consistent flow of broke to the machine furnish.

•List the functions of broke cleaning and screening systems •List safety hazards and safety guidelines related to broke systems •Explain the purpose of high density cleaners, broke deflakers, and broke screens in broke systems •Describe process flows in a typical broke cleaning and screening system •Describe the operation of a high density cleaner junk trap •Explain how a two-stage screening system works •Explain why consistency control is important in broke cleaning and screening systems •Describe why it is important for broke to be metered consistently into the machine furnish