A first refining disc (5) for a defibrator (1) for refining fibrous material, adapted to receive a flow of incoming fibrous material (7) from a feed screw (3a) through a material inlet opening (4) arranged in the first refining disc (5), is provided with at least one steam evacuating channel (21) comprising at least one steam inlet opening (22) arranged on a side of the first refining disc (5) adapted to face a second refining disc (6), and at least one steam outlet opening (23) arranged on a side of the first refining disc (5) adapted to face away from the second refining disc (6). The at least one steam outlet opening (23) is arranged centrally of the at least one steam inlet opening (22) with respect to the center of the first refining disc (5), and centrally of a position where the flow of incoming material (7) is to be received into the first refining disc (5) from the feed screw (3a), with respect to the center of the first refining disc (5).

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 equidistant curved bars, comprising following steps of: designing a central bar are of center curved bar and defining the bar angle for the equidistant curved bar; designing circle arcs for curved bars on two sides of center curved bar of equidistant curved bar segment; when the whole refining segment is full of circle arcs, trimming lines of outer circle arcs of the refining segment to complete the design of equidistant circle arcs on the two sides; and if required, dividing the bars into zones. In the present invention, by the definition of the bar angle for the curved bars and the parametric design of the equidistant curved bars by using circle are equations, it is ensured that the flexibility in designing an equidistant curved bar refiner plate is improved.

A disc-type refiner segment and a production method thereof are provided for refining lignocellulosic material, comprising providing production data of the disc-type refiner segment supplying the production data to a 3D printer; 3D printing a pattern of the disc-type refiner segment; using the pattern of the disc-type refiner segment to generate a mold of the of the disc-type refiner segment; and molding or casting the disc-type refiner segment using the mold.

A refiner segment for a refiner for defibrating has a refining surface comprising a group of first bars and second bars, each having a first end directed in the direction of an inlet zone and a second end directed in the direction of a refining zone, where the second ends of the first bars are interlaced with the first ends of the second bars to form first grooves between the first bars, and second grooves between the second bars. The second ends of the first bars have a guiding surface decreasing from an upper surface of the first bars down towards the bottom of the second grooves, and the first ends of the second bars have a guiding surface increasing from the bottom of the first grooves up to a top of the second bars, such that the guiding surfaces form an equalization groove.

This disclosure relates to a refiner plate segment, mechanical refiners, and methods to manufacture a refiner plate segment having one or more water channels disposed in a variable substrate profile along the radial length of a refiner plate segment base and disposed between the refiner plate segment inlet and the primary refining section, wherein the variable substrate profile comprises an undulating curve configured to complement a second undulating curve on an opposing refiner plate, and wherein dimensions of the one or more water channels are sufficiently narrow to prevent wood chips from entering the water channels and sufficiently wide to provide a bypass path for the free water.

A refining member comprising a refining body with a refining surface comprising first and second refiner bars separated by first and second refiner grooves, respectively. The first refiner bars extend from a radially inward position to a first radially outward position. The second refiner bars extend to a second radially outward position that is nearer to an outermost part of the refining body than the first radially outward position. The second refiner bars have a longitudinal length from about 0.6 cm to about 10 cm. The first and second refiner bars have a respective first and second maximum height extending upward from a floor of a respective, adjacent first or second refiner groove. The second maximum height is at least 0.35 mm less than the first maximum height. The first refiner bars are adapted to refine wood fibers and the second refiner bars are adapted to break up fiber bundles.

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 member for a pulp refiner comprising a refining body with a refining surface comprising refiner bars separated by refiner grooves and teeth. Each of the refiner bars extend from a radially inward position on the refining surface to a first radially outward position on the refining surface, and the teeth extend to a second radially outward position on the refining surface. The second radially outward position is nearer to an outermost part of the refining body than the first radially outward position. The refiner bars are adapted to refine wood fibers, and the teeth are adapted to break up fiber bundles.

A refiner segment for a refiner of lignocellulosic material includes a first bar, a second bar, a first dam, and a second dam. The first bar has a width and includes a first bar weakening section. The first bar weakening section includes two planar faces defining a wedge-shaped recess with a tip and a base. The two planar faces meet at the tip. The tip is separated from the base by a depth. The depth is greater than or equal to half of the width and less than or equal to the width. The first dam extends between the first bar and the second bar. The second dam extends between the first bar and the second bar. The first bar, the second bar, the first dam, and the second dam define a first essentially box-shaped region. The first bar weakening section is positioned within the first essentially box-shaped region.