Blade segment for refiner

A pair of refiner blade segments for mounting within a refiner for refining fibrous material, comprising:

• a first blade segment comprising:
• an inner end edge and an outer end edge;
• a first side edge and a second side edge opposite to the first side edge, the first side edge and the second side edge extending between the inner end edge and the outer end edge;
• a refining surface comprising blade bars and blade grooves therebetween forming a front surface of the first blade segment, and a rear surface opposite the front surface wherein a whole thickness of the first blade segment is defined between the front surface and the rear surface;
• wherein the rear surface is arranged to mount to the refiner;
• and wherein at least one of the first side edge and the second side edge of the first blade segment has portions forming a first opening between the front surface and the rear surface that extends from the at least one of the first side edge and the second side edge toward the opposite second side edge or first side edge such that the first opening extends through the whole thickness of the first blade segment, wherein the first opening is arranged to conduct fibrous material through the whole thickness of the first blade segment from a source of fibrous material to the refining surface;
• and a second blade segment comprising:
• an inner end edge and an outer end edge;
• a first side edge and a second side edge opposite to the first side edge, the first side edge and the second side edge extending between the inner end edge and the outer end edge;
• a refining surface comprising blade bars and blade grooves therebetween forming a front surface of the second blade segment, and a rear surface opposite the front surface wherein a whole thickness of the second blade segment is defined between the front surface and the rear surface;
• wherein the rear surface is arranged to mount to the refiner;
• and wherein at least one of the first side edge and the second side edge of the second blade segment has portions forming a first opening between the front surface and the rear surface that extends from the at least one of the first side edge and the second side edge toward the opposite second side edge or first side edge such that the first opening extends through the whole thickness of the second blade segment, wherein the first opening is arranged to conduct fibrous material through the whole thickness of the second blade segment from a source of fibrous material to the refining surface;
• and a feed groove on the refining surface, the feed groove cutting across the blade grooves and bars on the refining surface, the feed groove having a depth greater than the blade grooves and wherein the feed groove extends obliquely in a running direction toward both the outer end edge and the side edge of the second blade segment;
• and wherein when the pair of blade segments are assembled with the first side edge of one of the first or second blade segments abutting the second side edge of the other of the first or second blade segments to form an abutment, the first opening of either the first or second blade segments which extends through the whole thickness of the respective first or second blade segment is located at the abutment;
• and the feed groove on the second blade segment communicates and extends away from said first opening of either the first or second blade segment located at the abutment.