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.

A refining member including a refining body with a refining surface including first and second refiner bars separated by first and second refiner grooves. The first and second refiner bars extend from respective first and second radially inward positions to respective first and second radially outward positions. The first and second refiner bars have a respective first and second height extending upward from a floor of a respective, adjacent first or second refiner groove. The second height is a minimum height of the second refiner bars and is spaced apart from the second radially inward position, with the second height being at least about 0.35 mm less than the first height. The first refiner bars are adapted to refine wood fibers and the second refiner bars are adapted to break up fiber bundles.

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.

An experimental system for studying a refining mechanism and characteristic of a refiner plate, including a disc refiner unit, a first storage tank, a second storage tank, a circulating pump, a pipeline system, a detection device for measuring process variables including flow, pressure and temperature, and a data acquisition and control system. An operation parameter control system is provided to control an operation state of valves at different positions of the pipeline system to achieve the switching of the operation mode of the experimental system. The data acquisition and control system is configured to collect the parameters at different detection points. A method for operating the experimental system is also provided.

A blade segment (4, 8, 8a, 8b) for a refiner comprises an inner end edge (20) and an outer end edge (21) and a first side edge (22) and a second side edge (23) opposite to the first side edge (22), the first side edge (22) and the second side edge (23) extending between the inner end edge (20) and the outer end edge (21), and a refining surface (29) comprising blade bars (27) and blade grooves (28) therebetween on a front surface (25) of the blade segment (4, 8, 8a, 8b). At least one side edge (22, 23) of the blade segment (4, 8, 8a, 8b) comprises at least one opening (14a, 14b, 14c, 14d, 14e, 14f, 14g) that extends from the side edge (22, 23) toward the opposite side edge (22, 23).

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.

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.

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.

The present disclosure provides a refiner segment (1) for refining of lignocellulosic material. The refiner segment (1) have a surface comprising a plurality of bars (10.sub.j) extending along a direction between an inner periphery (17b) of the refining segment and an outer periphery (17b) of the refining segment (17b), and a plurality of dams (11.sub.i). Each of the dams extend between a corresponding pair of adjacent bars (10.sub.k, 10.sub.k+1). The refiner segment (10) comprises at least one dam (11.sub.p) that comprises a curved side (11c) facing the inner periphery (17b) of the refiner segment (1). The curved side (11c) have a concave curvature with regard to the inner periphery (17b) to thereby form a rounded section in an area (20) defined by the dam (11.sub.p) and the corresponding pair of adjacent bars (10.sub.k, 10.sub.k+1). The at least one dam (11.sub.p) is moreover a three dimensionally extending body. The rounded section created by the concave curvature gives a more robust refining segment. The present disclosure also provides a refiner disc that comprises such a refiner segment. The present disclosure additionally provides a refiner having at least one such refiner disc.

The invention relates to a center ring arrangeable on a refining disc of a defibrator for refining of fibrous material, wherein said center ring comprises a circumferential outer surface, a circumferential inner surface and a centrally located through-hole adapted to receive fibrous material fed from a feeding device, wherein said outer surface is provided with a circumferentially running groove opening up on the outer surface and being adapted to collect steam produced during operation of said defibrator, and wherein the center ring further comprises a plurality of wings provided on said inner surface and a number of channels extending from said groove to the positions on said inner surface where said wings are provided.