Abstract: Conical inlet refiner elements for a mechanical refiner include: a conical stator element disposed between a feedstock inlet to the mechanical refiner and primary refining plates of the mechanical refiner; and a conical rotor element disposed between the feedstock inlet to the mechanical refiner and the primary refining plates, the conical rotor element configured to form an initial refining gap with the conical stator element. The conical stator element and the conical rotor element are configured to cause a radial change greater than zero but less than 90 degrees in a direction of an axial feedstock flow path through the initial refining gap at a feedstock inlet to a primary refining gap formed between the primary refining plates, where the primary refining gap formed between the primary refining plates lies in a plane that is approximately perpendicular to the axial feedstock flow path.