High Density Cleaners
High density (or HD) cleaners are large diameter forward cleaners capable of processing several hundred tons of fiber per day. The main purpose of high density cleaners is to separate heavy contaminants from fibers in suspensions of fibers in water (often referred to as “stock”). This protects downstream equipment from excessive wear and damage. They may also be used for fiber recovery. This module will describe the operation of high density cleaners and identify typical applications of high density cleaners in secondary fiber, pulp mill, stock preparation, and broke systems.





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Course Details
Learning Objectives
• Describe how high density cleaners differ from other centrifugal cleaners • Identify safety hazards associated with high density cleaners • Identify the purpose of high density cleaners • Describe the operation of a “junk trap” during a dump cycle • Describe the purpose of the main components of a junk trap • Identify typical applications of high density cleaners in secondary fiber, pulp mill, stock preparation, and broke systems
Specs
Frequently Asked Questions
What is the purpose of high density cleaners?
Where are high density cleaners typically used?
How are high density cleaners different from other forward cleaners used in the production of paper and board?
What is the purpose of the elutriation water in a high density cleaner?
How often are the junk traps on high density cleaners emptied?
Sample Video Transcript
High-density cleaners are specifically designed to remove high and medium-density contaminants or contaminants with high and medium specific gravities from stock. Contaminants such as rocks, nuts, bolts, nails, paperclips, staples, glass, and other heavy debris are removed by the cleaner. High-density cleaners are not designed to remove wax or other low-density or low specific gravity materials. The stock suspension is pumped tangentially into the top of the cylindrical cleaner body at relatively high velocity. As the stock flows inward, centrifugal force and fluid sheer create a vortex near the center of the cleaner. Dense materials move to the outside wall and drop down into a bottom rejects collection chamber. The fibers migrate to the center vortex and travel upwards to the accepted stock outlet.