Forces on fibres in low-consistency refining: Normal force

D. M. Martinez, W. J. Batchelor, R. J. Kerekes, D. Ouellet

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42 Citations (Scopus)


An expression has been derived to predict the force acting on an ideal floc undergoing compression between passing bars of a refiner. The model equations are based upon three assumptions about flocs: they are spherical in shape with fibres evenly spaced in any cross-section; they cannot support significant normal load until the majority of fibres are in contact; and they display linear elastic behaviour under compression. The validity of the expression was tested in a single-bar refiner operating at 1 rpm, using model nylon floes. Good agreement was found between the experimental measurements and the derived expression. The results indicate that the force increased sharply over the first 2-3 mm of the bar, and then remained essentially constant over the remaining width of the bar.

Original languageEnglish
JournalJournal of Pulp and Paper Science
Issue number1
Publication statusPublished - 1 Jan 1997
Externally publishedYes


  • Compression
  • Fibers
  • Flocs
  • Force
  • Low consistency
  • Mathematical models
  • Refiners
  • Refining

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