Refiner

1. A refiner ( 1 ) comprising a stator ( 2 ) and a rotor ( 4 ), the stator ( 2 ) and the rotor ( 4 ) comprising a flat portion ( 7 , 9 ) and a conical portion ( 8 , 10 ), the conical portion ( 8 ) having a first end ( 17 ) of smaller diameter (D 1 ) and a second end ( 18 ) of greater diameter (D 2 ) such that the first end ( 17 ) of the conical portion ( 8 , 10 ) having smaller diameter (D 1 ) is directed towards the flat portion ( 7 , 9 ) and the second end ( 18 ) of the conical portion ( 8 , 10 ) having greater diameter (D 2 ) is directed away from the flat portion ( 7 , 9 ), and which flat portion ( 7 , 9 ) and the conical portion ( 8 , 10 ) comprise refining surfaces ( 11 , 12 , 13 , 14 ) provided with blade bars ( 20 ) and blade grooves ( 21 ) therebetween, and that

the refining surface ( 12 ) of the conical portion ( 8 ) of the stator ( 2 ) comprises at least an outer zone ( 23 ) arranged at the second end ( 18 ) of the conical portion ( 8 ) having greater diameter (D 2 ) and an inner zone ( 22 ) arranged relative to the outer zone ( 23 ) on the side of the first end ( 17 ) of the conical portion ( 8 ) having smaller diameter (D 1 ), the length of the outer zone ( 23 ) being half of the total length (D) between the first end ( 17 ) and the second end ( 18 ) of the conical portion ( 8 ) of the stator ( 2 ) and that

a portion of the length of the blade bars ( 20 ) in the outer zone ( 23 ) of the conical portion ( 8 ) of the stator ( 2 ) create a negative blade bar angle (α) having a value of minus 1 degree to minus 30 degrees relative to the rotation direction (RD) of the rotor ( 4 ) such that they have a retentive effect on the material to be refined and that

this portion of the length of the blade bars ( 20 ) in the outer zone ( 23 ) of the conical portion ( 8 ) of the stator ( 2 ) corresponds to at least 10% of the total length (D) between the first end ( 17 ) and the second end ( 18 ) of the conical portion ( 8 ) of the stator ( 2 ).

2. A refiner according to claim 1 , wherein the portion of the length of the blade bars ( 23 ) in the outer zone ( 23 ) of the conical portion ( 8 ) of the stator ( 2 ), which portion of the length of the blade bars ( 23 ) creates a negative blade bar angle (α) having a value of minus 1 degree to minus 30 degrees relative to the rotation direction of the rotor ( 4 ), corresponds to at least 30% of the total length between the first end ( 17 ) and the second end ( 18 ) of the conical portion ( 8 ).

3. A refiner according to claim 1 , wherein the length of the blade bars ( 20 ) of the conical portion ( 8 ) of the stator ( 2 ), which blade bars ( 20 ) create a negative blade bar angle (α) having a value of minus 1 degree to minus 30 degrees relative to the rotation direction (RD) of the rotor ( 4 ), correspond to the total length between the first end ( 17 ) and the second end ( 18 ) of the conical portion ( 8 ).

4. A refiner according to claim 1 , wherein the blade bar angle (α) has a value of minus 1 degree to minus 20 degrees relative to the rotation direction (RD) of the rotor ( 4 ).

5. A refiner according to claim 1 , wherein the blade bar angle (α) has a value of minus 2 degrees to minus 10 degrees relative to the rotation direction (RD) of the rotor ( 4 ).

6. A refiner according to claim 1 , wherein the blade bars ( 20 ) are arranged in the inner zone ( 22 ) of the conical portion ( 8 ) of the stator ( 2 ) such that the blade bars create a negative blade bar angle (α) relative to the rotation direction (RD) of the rotor ( 4 ) in the inner zone ( 22 ) of the conical portion ( 8 ) of the stator ( 2 ).

7. A refiner according to claim 1 , wherein the blade bars ( 20 ) are arranged in the inner zone ( 22 ) of the conical portion ( 8 ) of the stator ( 2 ) such that the blade bars create a positive blade bar angle (α) relative to the rotation direction (RD) of the rotor ( 4 ) in the inner zone ( 22 ) of the conical portion ( 8 ) of the stator ( 2 ).

8. A refiner according to claim 7 , wherein the length of the inner zone ( 22 ) corresponds to at least one-quarter of the total length between the first end ( 17 ) and the second end ( 18 ) of the conical portion ( 8 ) of the stator ( 2 ), the inner zone ( 22 ) being located at some portion of the conical portion ( 8 ) of the stator ( 2 ) between the first end ( 17 ) of the conical portion ( 8 ) having a smaller diameter (D 1 ) and the outer zone ( 23 ).

9. A refiner according to claim 8 , wherein the length of the inner zone ( 22 ) corresponds to half of the total length between the first end ( 17 ) and the second end ( 18 ) of the conical portion ( 8 ) of the stator ( 2 ).

10. A refiner according to claim 1 , wherein the refiner ( 1 ) is a high-consistency refiner.

11. A blade segment ( 19 ) of a refiner ( 1 ), the blade segment ( 19 ) comprising:

blade bars ( 20 ) and blade grooves ( 21 ) therebetween, which together form a refining surface ( 12 ) of a conical portion ( 8 ) of a stator ( 2 ) of the refiner ( 1 );

an outer zone ( 23 ) arrangeable at a second end ( 18 ) of the conical portion ( 8 ), the second end ( 18 ) having a diameter (D 2 ); and

an inner zone ( 22 ) arrangeable relative to the outer zone ( 23 ) on the side of a first end ( 17 ) of the conical portion ( 8 ), the first end ( 17 ) having a diameter (D 1 ) smaller than the diameter (D 2 ) of the second end ( 18 ), the length of the outer zone ( 23 ) being half of a total length (D) of the blade segment ( 19 ),

wherein:

a portion of a length of the blade bars ( 20 ) in the outer zone ( 23 ) of the blade segment ( 19 ) are arrangeable to create a negative blade bar angle (α) having a value of minus 1 degree to minus 30 degrees relative to the rotation direction (RD) of the rotor ( 4 ) such that they have a retentive effect on the material to be refined; and

the portion of the length of the blade bars ( 20 ) in the outer zone ( 23 ) of the blade segment ( 19 ) corresponds to at least 10% of the total length (D) of the blade segment ( 19 ).

12. A blade segment according to claim 11 , wherein the portion of the length of the blade bars ( 20 ) in the outer zone ( 23 ) of the conical portion ( 8 ) of the stator ( 2 ), which portion of the length of the blade bars ( 20 ) creates a negative blade bar angle (α) having a value of minus 1 degree to minus 30 degrees relative to the rotation direction (RD) of the rotor ( 4 ), corresponds to at least 30% of the total length of the blade segment ( 19 ).

13. A blade segment according to claim 11 , wherein the length of the blade bars ( 20 ) of the blade segment ( 19 ), which blade bars ( 20 ) are arrangeable to create a negative blade bar angle (α) having a value of minus 1 degree to minus 30 degrees relative to the rotation direction (RD) of the rotor ( 4 ), correspond to the total length of the blade segment ( 19 ).

14. A blade segment according to claim 11 , wherein the blade bar angle (α) has a value of minus 1 degree to minus 20 degrees relative to the rotation direction (RD) of the rotor ( 4 ).

15. A blade segment according to claim 11 , wherein the blade bar angle (α) has a value of minus 2 degrees to minus 10 degrees relative to the rotation direction (RD) of the rotor ( 4 ).

16. A blade segment according to claim 11 , wherein the blade bars ( 20 ) are arranged in the inner zone ( 22 ) of the blade segment ( 19 ) such that the blade bars are ( 22 ) arrangeable to create a negative blade bar angle (α) relative to the rotation direction (RD) of the rotor ( 4 ) in the inner zone ( 22 ) of the conical portion ( 8 ) of the stator ( 2 ).

17. A blade segment according to claim 11 , wherein the blade bars ( 20 ) are arranged in the inner zone ( 22 ) of the blade segment ( 19 ) such that the blade bars ( 20 ) are arrangeable to create a positive blade bar angle (α) relative to the rotation direction (RD) of the rotor ( 4 ) in the inner zone ( 22 ) of the conical portion ( 8 ) of the stator ( 2 ).

18. A blade segment according to claim 17 , wherein the length of the inner zone ( 22 ) corresponds to at least one-quarter of the total length of the blade segment ( 19 ), the inner zone ( 22 ) being located at some portion of the blade segment ( 19 ) between the inner periphery of the blade segment ( 19 ) and the outer zone ( 23 ) of the blade segment ( 19 ).

19. A blade segment according to claim 18 , wherein the length of the inner zone ( 22 ) corresponds to half of the total length between the first end ( 17 ) and the second end ( 18 ) of the conical portion ( 8 ) of the stator ( 2 ).