Mini-Encyclopedia of Papermaking Wet-End
Part Three: Equipment & Unit Operations
When papermakers use the word "cleaning" they are referring to the action of hydrocyclones. A hydrocyclone is a conical or partly cylindrical device with no moving parts, except for the fibrous slurry that flows through it. The slurry enters the hydrocyclone at a tangent along its widest part. Rapid rotation of the fluid within the hydrocyclone throws dense materials toward the outside. Conventional high-intensity forward cleaners of the type used in most paper machine systems reject the dense materials from the small end of the cone, along with about 10 to 30 percent of the flow. It is conventional practice to connect three or more banks of cleaners, using the rejects from one stage as the feed for the next. The accepts from a secondary stage of cleaning can be used as feed for the primary cleaners, etc.
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