Patent ID: 11891758
Assignee: VALMET TECHNOLOGIES OY
Field: Textile and paper machines (Mechanical engineering)
Classification: CPC D | IPC D

Claim 13:
14. A blade element pair for a refiner for refining fibrous material comprising:
at least one first blade element for mounting to the refiner to rotate about an axis defining an axial direction and a radial direction, the at least one first blade element having a first refining surface extending in at least one of the radial direction and the axial direction, the first refining surface having first blade bars and first blade grooves therebetween, the first blade bars and first grooves extending along the first blade element in at least one of the radial direction and the axial direction and wherein the at least one first blade element has first openings for the passage therethrough of material to be refined which extend through the at least one first blade element in at least one of the radial direction and the axial direction, wherein the first openings have a first length in the radial direction;
at least one second blade element for mounting to the refiner, the at least one second blade element having a second refining surface extending in at least one of the radial direction and the axial direction, the second refining surface having second blade bars and second blade grooves therebetween and extending along the second blade element in at least one of the radial direction and the axial direction and wherein the at least one second blade element has second openings for the passage therethrough of material to be refined which extend through the second blade element in at least one of the radial direction and the axial direction, wherein the second openings have a second length in the radial direction which is greater than the first length;
wherein the at least one first blade element and the at least one second blade element when mounted to the refiner are set substantially opposed to each other in such a manner that the first and second refining surfaces are opposed such that a refiner chamber for receiving material to be refined is formed therebetween; and
wherein the first openings in the first blade element and the second openings in the second blade openings are arranged at different axial or radial positions such that material to be refined does not pass between the first openings and the second openings without engaging the first refining surface and the second refining surface.