The present invention relates to a blade for a disc refiner intended for refining lignocellulosic material, the blade (10) comprising a surface (1) delimited by an inner circumference (11) and an outer circumference (12), a refiner zone (2) on the surface (1) for refining lignocellulosic material, a blank zone (3) on the surface (1), wherein the refiner zone (2) is arranged closer to the inner circumference (11) than the blank zone (3), the blade (10) further comprising a separation groove (4) that is arranged between the refiner zone (2) and the blank zone (3), and at least one connecting groove (5) that connects the separation groove (4) to the outer circumference (12) of the blade (10) across the blank zone (3). The invention also relates to a blade pair and to a refiner comprising at least one blade.

The present invention relates to a blade for a disc refiner intended for refining lignocellulosic material, the blade (10) comprising a surface (1) delimited by an inner circumference (11) and an outer circumference (12), a refiner zone (2) on the surface (1) for refining lignocellulosic material, a blank zone (3) on the surface (1), wherein the refiner zone (2) is arranged closer to the inner circumference (11) than the blank zone (3), the blade (10) further comprising a separation groove (4) that is arranged between the refiner zone (2) and the blank zone (3), and at least one connecting groove (5) that connects the separation groove (4) to the outer circumference (12) of the blade (10) across the blank zone (3). The invention also relates to a blade pair and to a refiner comprising at least one blade.

This disclosure relates to refiner plate segments having feeding grooves having a first width at a first end of the feeding groove, wherein the first end of the feeding groove is disposed closer to an inner diameter of the refiner plate segment, and a second end of the feeding groove having a second width, wherein the second end of the feeding groove is disposed closer to the outer diameter than the first end and wherein the second width is less than the first width. It is believed that the increased width of the feeding groove at the inner diameter, coupled with the change in angle or curve of the feed groove from a feeding angle to a holding angle such that the centrifugal force applied to the lignocellulosic material surpasses the plugging force, allows for improved hydraulic capacity over the refiner plate segment without reducing refining efficiency.

This disclosure relates to refiner plate segments having feeding grooves having a first width at a first end of the feeding groove, wherein the first end of the feeding groove is disposed closer to an inner diameter of the refiner plate segment, and a second end of the feeding groove having a second width, wherein the second end of the feeding groove is disposed closer to the outer diameter than the first end and wherein the second width is less than the first width. It is believed that the increased width of the feeding groove at the inner diameter, coupled with the change in angle or curve of the feed groove from a feeding angle to a holding angle such that the centrifugal force applied to the lignocellulosic material surpasses the plugging force, allows for improved hydraulic capacity over the refiner plate segment without reducing refining efficiency.

A refining disc (6) in a defibrator (1) for refining fibrous material is provided with non-central openings (11) for allowing steam developed in the refining space (2) during refining to flow from the front side to the backside of the refining disc (6), where the front side is facing a second refining disc (5) and the backside is facing away from the second refining disc (5). The refining disc (6) also comprises a central hole (12) for allowing steam (8b) to flow from the backside to the front side at the rotational center of the refining disc (6), and escape from the defibrator (1) backwards through the feed screw (3a) without passing through the fibrous material (7) being refined in the refining space (2).

A refining disc (6) in a defibrator (1) for refining fibrous material is provided with non-central openings (11) for allowing steam developed in the refining space (2) during refining to flow from the front side to the backside of the refining disc (6), where the front side is facing a second refining disc (5) and the backside is facing away from the second refining disc (5). The refining disc (6) also comprises a central hole (12) for allowing steam (8b) to flow from the backside to the front side at the rotational center of the refining disc (6), and escape from the defibrator (1) backwards through the feed screw (3a) without passing through the fibrous material (7) being refined in the refining space (2).

The present invention discloses a method for designing a refiner plate with three-stage radial curved bars, comprising following steps of: designing a circle arc for 1.sub.st stage radial curved bars; designing a circle arc for the 2.sub.nd stage radial curved bars; designing a circle arc for 3.sub.rd stage radial curved bars; and designing a center angle for the refiner plate according to the size of the refiner plate and the manufacture requirements, to complete the design of the refiner plate. In the present invention, by the establishment of equations for the circle arcs and angles of inclination of the curved bars, it is ensured that the width of the bars will not change in the radial direction, and both the flexibility in designing a curved refiner plate and the uniformity of crushing are improved. This design method provides a theory basis and also instructions for designing multi-stage radial curved bars.

The present invention discloses a method for designing a refiner plate with three-stage radial curved bars, comprising following steps of: designing a circle arc for 1.sub.st stage radial curved bars; designing a circle arc for the 2.sub.nd stage radial curved bars; designing a circle arc for 3.sub.rd stage radial curved bars; and designing a center angle for the refiner plate according to the size of the refiner plate and the manufacture requirements, to complete the design of the refiner plate. In the present invention, by the establishment of equations for the circle arcs and angles of inclination of the curved bars, it is ensured that the width of the bars will not change in the radial direction, and both the flexibility in designing a curved refiner plate and the uniformity of crushing are improved. This design method provides a theory basis and also instructions for designing multi-stage radial curved bars.

The disclosure relates to a method for producing of refiner disc segments. The method for producing of the invention allows for forming a multitude of refiner segments with only one forming process of a first die which may be lightweight and has reduced cost while at the same time a surface structure with high hardness which reduces wear of the die's surface. The method for producing a disc-type refiner segment for refining lignocellulosic material includes 3D printing a first model; forming a first die part using investment casting; 3D printing a second model; combining the first die part and the second model to create a first die model; using the first die model to generate for forming a sand model by compressing molding sand between the first die and the second die; and casting a refiner disc segment by casting a metal material using the sand model.

A refiner plate segment including a plurality of bars and grooves for refining lignocellulosic materials, where the grooves between adjacent bars includes a plurality of teeth having a wave-like profile with alternating high and low points. The wave-like profile of the teeth within the grooves increases turbulence in the refining process to tumble the fibers and push them toward the refining gap to reduce energy and improve the efficiency of the fiber reduction process.