The Effect of Thrust on the Development of Strength with the Mead Refiner

Several different thrust pressures were exerted on the plates of the Mead Laboratory Refiner and pulp samples were refined over a wide freeness range for each of the several pressures. The strength characteristics developed were measured and it was found that maximum burst and tensile strength was developed by a thrust pressure of 31.22 pounds. Maximum tearing strength was developed at a thrust pressure of 25.94 pounds. The refining time required to reach a given freeness increased as as the thrust was reduced, but reached a maximum at 20.66 pounds and remained constant for lesser pressures