Patent ID: 7726596

Claim:
A fibrous slurry refiner comprising: a casing; a rotor secured to a rotor shaft, the rotor being disposed within the casing and rotatable via the rotor shaft; a first plurality of grinding surfaces secured to the rotor; a second plurality of grinding surfaces disposed facing the first plurality of grinding surfaces and being fixed in the casing; and an inlet housing made up of an inlet plate, an axial cylinder and a spiral inlet opening for each of the plurality of grinding surfaces, each inlet plate directing the fibrous slurry toward a set of facing first and second grinding surfaces and imparting a rotary flow to the fibrous slurry, wherein the axial cylinder is substantially circular, wherein the spiral inlet opening is positioned tangentially relative to a center of inlet plate, and wherein the inlet housing comprises a spiral channel extending from the inlet opening to the center of the inlet plate.