Patent ID: 8328124

Claim:
A method of mechanically refining lignocellulosic material in a refiner having opposing refiner plates, the method comprising: introducing the material to an inlet in one of the opposing refiner plates; rotating at least one of the plates with respect to the other plate, wherein the material moves radially outward through a gap between the plates due to centrifugal forces created by the rotation; as the material moves through the gap, passing the material over bars in a refiner zone of a first one the plates, each bar in the refiner zone having a leading face and a planar upper ridge, wherein the leading face includes a sidewall of the bar facing a direction of rotation of the opposing plate and an entirety of an upper sidewall section of the sidewall forms an interior angle with to the upper ridge of between 150 degrees to 175 degrees, and discharging the material from the gap at a periphery of the refiner plates.