Valmet Ab

Karl Lönngren

Mikael Lundfors

Christer Hedlund

A double disc refiner includes a first refining disc at a feed end and an opposing second refining disc. The first disc has inlet opening(s) and a first distal surface facing a second disc opposing surface. A first disc refining segment has a second distal surface facing the opposing surface that has a first height relative to a plane of the first distal surface in a direction toward the opposing surface. A first disc center plate has elongated protrusions radially extending therefrom and a third distal surface having a second height in the direction of the first height that is at least equal to the first height. Each protrusion has a fourth distal surface continuous with the third distal surface and a third height in the direction of the first height equal to the second height. The third distal surface is separated from the opposing surface by 5-15 mm.

Double-disc refiner

A refiner for refining of lignocellulosic material includes a rotor disc and a stator disc. The rotor disc includes a first refining segment that includes a plurality of first protruding structures for grinding of the lignocellulosic material. Each of the first protruding structures is defined by a first height. The stator disc is arranged opposite the rotor disc and includes a second refining segment that includes a plurality of second protruding structures for grinding of the lignocellulosic material. Each of the second protruding structures being defined by a second height. The first height is at least three times larger than the second height.

Refiner for refining lignocellulosic material and refining segments for such a refiner

A refining disc () in a defibrator () for refining fibrous material is provided with non-central openings () for allowing steam developed in the refining space () during refining to flow from the front side to the backside of the refining disc (), where the front side is facing a second refining disc () and the backside is facing away from the second refining disc (). The refining disc () also comprises a central hole () for allowing steam () to flow from the backside to the front side at the rotational center of the refining disc (), and escape from the defibrator () backwards through the feed screw () without passing through the fibrous material () being refined in the refining space ().

Steam evacuation in a pulp or fiber refiner

A center plate for a rotor in a pulp refiner is described in which the center plate is provided with a plurality of first wings for directing pulp flowing onto the center portion of the center plate towards the periphery of the center plate, each of the first wings comprising an arc-shaped protrusion extending between a corresponding first point and a corresponding second point on the surface of the center plate, the first point being displaced from the center portion of the center plate and the second point being disposed further from said center portion of the center plate then the first point, the first wings having an arc shape that yields a larger pulp feeding angle then that of a circular arc intersecting the center portion of the center plate and ending in the same corresponding second point, and the second point of each of the first wings lies on the periphery of the center plate.

Growing community of inventors

Stockholm, Sweden

Karl Lönngren