Technology for efficiently extracting fiber from a feedstock containing fiber. A subunit has a mesh drum configured as a rotatable cylinder with mesh in at least part of its surface, and a case that houses the mesh drum. The case has a first opening and a second opening that communicate with a first area, and a third opening that communicates with a second area. First screened material is supplied from the first opening to the first area. The subunit discharges from the third opening waste, which is a first component of the first screened material moved by an air current from the first area to the second area, and discharges from the second opening by an air current processing feedstock, which is a second component of the first screened material that does not pass through the mesh drum with the air current and remains in the first area.

The present invention relates to a screen cylinder that is particularly suitable for screening, filtering, fractionating, or sorting cellulose pulp or fibre suspensions of the pulp and paper industry or other similar suspensions. The present invention relates more particularly to screening devices, which are usually cylindrical though also conical shapes are known. Such screening devices have basically two optional constructions. A first one comprises a plurality of screen wires positioned substantially axially and at a small spacing parallel to each other. The plurality of screen wires forms a screening surface facing the pulp or fibre suspension to be screened and adjacent wires form screening openings therebetween allowing an accept portion of the pulp or fibre suspension to flow therethrough. The second construction comprises a drilled or slotted sheet metal plate bent to a circular, or in broader terms, rotationally symmetrical shape.

The present invention relates to a screen cylinder that is particularly suitable for screening, filtering, fractionating, or sorting cellulose pulp or fibre suspensions of the pulp and paper industry or other similar suspensions. The present invention relates more particularly to screening devices, which are usually cylindrical though also conical shapes are known. Such screening devices have basically two optional constructions. A first one comprises a plurality of screen wires positioned substantially axially and at a small spacing parallel to each other. The plurality of screen wires forms a screening surface facing the pulp or fibre suspension to be screened and adjacent wires form screening openings therebetween allowing an accept portion of the pulp or fibre suspension to flow therethrough. The second construction comprises a drilled or slotted sheet metal plate bent to a circular, or in broader terms, rotationally symmetrical shape.

Disclosed is a refiner filling piece for a refiner having a rotor that rotates about an axis of rotation and cooperates with a stator to mechanically treat a pulp containing cellulosic fibers. The refiner filling piece is mountable to the rotor or the stator. The refiner filling piece comprises a base and a plurality of spaced-apart refiner bars, each refiner bar being defined by a bar length and a bar height. At least some of the refiner bars have a surface coated with a variable coating. The surface having the variable coating may be the leading surface of the bar.

Disclosed is a refiner filling piece for a refiner having a rotor that rotates about an axis of rotation and cooperates with a stator to mechanically treat a pulp containing cellulosic fibers. The refiner filling piece is mountable to the rotor or the stator. The refiner filling piece comprises a base and a plurality of spaced-apart refiner bars, each refiner bar being defined by a bar length and a bar height. At least some of the refiner bars have a surface coated with a variable coating. The surface having the variable coating may be the leading surface of the bar.

The present invention relates to a screen cylinder that is particularly suitable for screening, filtering, fractionating, or sorting cellulose pulp or fibre suspensions of the pulp and paper industry or other similar suspensions. The present invention relates more particularly to screening devices, which are usually cylindrical though also conical shapes are known. Such screening devices have basically two optional constructions. A first one comprises a plurality of screen wires positioned substantially axially and at a small spacing parallel to each other. The plurality of screen wires forms a screening surface facing the pulp or fibre suspension to be screened and adjacent wires form screening openings therebetween allowing an accept portion of the pulp or fibre suspension to flow therethrough. The second construction comprises a drilled or slotted sheet metal plate bent to a circular, or in broader terms, rotationally symmetrical shape.

The present invention relates to a screen cylinder that is particularly suitable for screening, filtering, fractionating, or sorting cellulose pulp or fibre suspensions of the pulp and paper industry or other similar suspensions. The present invention relates more particularly to screening devices, which are usually cylindrical though also conical shapes are known. Such screening devices have basically two optional constructions. A first one comprises a plurality of screen wires positioned substantially axially and at a small spacing parallel to each other. The plurality of screen wires forms a screening surface facing the pulp or fibre suspension to be screened and adjacent wires form screening openings therebetween allowing an accept portion of the pulp or fibre suspension to flow therethrough. The second construction comprises a drilled or slotted sheet metal plate bent to a circular, or in broader terms, rotationally symmetrical shape.

A method for producing a cylindrical screen device with a plurality of profiled bars. The outer face of a plurality of mutually spaced annular bar holders, which are arranged perpendicular to the cylinder axis, are provided with recesses that are open at the edges. The recesses have a shape that substantially corresponds to the base of profiled bars in a complimentary manner. The recesses are marginally larger than the bases. The profiled bars are inserted into respective recesses, parallel to one another and parallel to cylinder axis.

A bar-type screen cage has profiled screen bars which are spaced apart in a circumferential direction. Multiple support arrangements which are spaced apart in an axial direction of the screen cage are fastened by welding to the profile bars at the outside. The screen bars, which are spaced apart in an axial direction, form screen slots between them. Each support arrangement includes at least two support wires which are closely spaced apart in the axial direction of the screen bars and which are fixed to the screen bars by resistance welding. The two support wires of each support arrangement and the profile bars-are fixedly connected to one another by way of an additional weld seam.

A bar-type screen cage has profiled screen bars which are spaced apart in a circumferential direction. Multiple support arrangements which are spaced apart in an axial direction of the screen cage are fastened by welding to the profile bars at the outside. The screen bars, which are spaced apart in an axial direction, form screen slots between them. Each support arrangement includes at least two support wires which are closely spaced apart in the axial direction of the screen bars and which are fixed to the screen bars by resistance welding. The two support wires of each support arrangement and the profile bars-are fixedly connected to one another by way of an additional weld seam.