Abstract: In a method for manufacturing fibril cellulose, cellulose based fibre raw material is processed mechanically in a refining gap for separating fibrils. The fibres to be refined are subjected to the action of a surface roughness Ra provided by grits elevated from a refining surface delimiting the refining gap, said surface roughness being lower than 3 ?m, advantageously lower than 2 ?m. The refining surface is formed by spraying grits and binder onto a substrate.

Abstract: Described herein is nanocellulose produced by introducing a mixture of cellulose based fiber raw material and water through a refining gap, having a width smaller than 0.1 mm. In the refining gap, the fiber raw material is subjected to processing forces varying in the direction of introducing said mixture, by means of refining zones provided in the gap one after each other in the feeding direction, whereby the refining surfaces differ in surface patterning and/or surface roughness. The mixture of fiber raw material and water is guided past the refining surfaces in the feeding direction to different locations in the refining zone by by-pass channels provided in the stator. The width of the refining gap is maintained by the combined effect of the feeding pressure of the mixture of fiber raw material and water fed into the refining gap and the axial force of the rotor.

Abstract: Described herein is nanocellulose produced by introducing a mixture of cellulose based fiber raw material and water through a refining gap, having a width smaller than 0.1 mm. In the refining gap, the fiber raw material is subjected to processing forces varying in the direction of introducing said mixture, by means of refining zones provided in the gap one after each other in the feeding direction, whereby the refining surfaces differ in surface patterning and/or surface roughness. The mixture of fiber raw material and water is guided past the refining surfaces in the feeding direction to different locations in the refining zone by by-pass channels provided in the stator. The width of the refining gap is maintained by the combined effect of the feeding pressure of the mixture of fiber raw material and water fed into the refining gap and the axial force of the rotor.

Abstract: A system for mechanical defibration of wood kneads the wood by moving a defibration surface having contours at least partly in contact with the wood in a direction at a speed in relation to the wood and fibres are separated from the wood. The contours of the defibration surface are at regular intervals in the direction that the speed and the regular intervals determine a cycle time-length that is 1 to 3 times a relaxation time of the wood.