Conical Refining Filling

A conical refiner for refining fibrous material, the conical refiner comprising:

• a main frame,
• a refiner chamber supported to the main frame;
• a feed end frame supported to the refiner chamber;
• a conical stator surrounded at least partly by the feed end frame;
• a conical rotor surrounded at least partly by the conical stator such that there is a refining gap between the stator and the rotor, the refining gap having a first end facing at least partly towards an inlet for fibrous material and a second end extending up to the refiner chamber;
• an outlet for the refined fibrous material communicating with the refiner chamber;
• wherein the stator comprises a conical refining filling having an inner circumference comprising a refining surface provided with refining bars and refining grooves which faces the rotor, and having an outer circumference, and wherein at least one projecting part extends from the outer circumference, the at least one projecting part projecting away from the outer circumference towards the feed end frame, a recirculation passageway being defined between the outer circumference of the stator and the feed end frame;
• and
• at least one opening defined in the at least one projecting part for the recirculation flow therethrough of fibrous material circulated from the refiner chamber back to the refining gap.

A method for refining fibrous material in a conical refiner comprising:

• introducing a fibrous material into an inlet in a conical refiner;
• passing the introduced fibrous material to a refining gap between a conical rotor and a conical stator having refining bars and refining gaps thereon thereby refining the fibrous material and discharging it into a refiner chamber;
• and
• passing a first portion of the refined fibrous material from the refiner chamber to a recirculation passage defined between the conical stator and a surrounding frame portion, the first portion of the refined fibrous material entering the recirculation passage through at least one opening in a projecting part which extends outwardly from an outer circumference of the conical stator, the projecting part extending to the surrounding frame portion.