Forces on Bars in High-Consistency Mill Scale Refiners: Effect of Consistency, 2007 International Mechanical Pulping Conference

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Laboratory experiments have shown that thermo-mechanical-pulp refiner process consistency can greatly affect the contact mechanics of bar-crossing impacts, specifically the shear forces. This effect was quantified using the equivalent tangential coefficient of friction,µ_teq, of the recorded impact. In this work, arrays of piezo-based sensors capable of measuring normal and shear forces on bars, were installed in two high-consistency, mill-scale refiners, one operating as a primary stage, and the other, as a rejects stage. An increase in refining consistency, measured at the discharge, was observed to cause an increase in µ_teq in the primary refiner, while no significant changes in µ_teq were observed in the rejects refiner. These results confirm the existence of a relationship between teqµand consistency at the mill-scale.