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.

A screen cylinder includes a cylindrical screening media having an inflow side and an outflow side. The screening media is formed of a plurality of circumferentially spaced an axially extending wedgewire bars, which have an inflow surface facing the inflow side. The axially extending wedgewire bars have a profile shape optimized to apply a spray on wear resistant coating on their inflow surface.

A screen cylinder includes a cylindrical screening media having an inflow side and an outflow side. The screening media is formed of a plurality of circumferentially spaced an axially extending wedgewire bars, which have an inflow surface facing the inflow side. The axially extending wedgewire bars have a profile shape optimized to apply a spray on wear resistant coating on their inflow surface.

A method of removing solid contaminants from a solid suspension may comprise: contacting the solid suspension with a screen cylinder comprising: a plurality of profiled bars aligned longitudinally, each of the plurality of profiled bars comprising: a first slot surface extending from an outer surface to an attachment end; a second slot surface opposite the first slot surface; and a hardened layer integral with or disposed on at least a portion of the first slot surface, the hardened layer having a Vickers hardness value greater than or equal to 500HV0.05; and; wherein contact of the solid suspension with the screen cylinder causes at least a portion of the solid suspension to pass through the slots; and collecting an acceptable solid suspension from the plurality of slots of the screen cylinder.

A method of removing solid contaminants from a solid suspension may comprise: contacting the solid suspension with a screen cylinder comprising: a plurality of profiled bars aligned longitudinally, each of the plurality of profiled bars comprising: a first slot surface extending from an outer surface to an attachment end; a second slot surface opposite the first slot surface; and a hardened layer integral with or disposed on at least a portion of the first slot surface, the hardened layer having a Vickers hardness value greater than or equal to 500HV0.05; and; wherein contact of the solid suspension with the screen cylinder causes at least a portion of the solid suspension to pass through the slots; and collecting an acceptable solid suspension from the plurality of slots of the screen cylinder.

A screen cylinder includes: a plurality of profiled bars aligned longitudinally and coupled to at least one support ring, each of the plurality of profiled bars comprising: an outer surface; a first slot surface extending from the outer surface to the attachment end of the profiled bar opposite the outer surface; a second slot surface opposite the first slot surface and extending from the outer surface to the attachment end of the profiled bar, wherein the first slot surface of one profiled bar and the second slot surface of another immediately adjacent profiled bar define a slot; and a hardened layer disposed on at least a portion of the first slot surface of the profiled bar, wherein the hardened layer is disposed directly on at least a portion of the first slot surface of the profiled bar and the hardened layer is an outer layer.

A screen cylinder includes: a plurality of profiled bars aligned longitudinally and coupled to at least one support ring, each of the plurality of profiled bars comprising: an outer surface; a first slot surface extending from the outer surface to the attachment end of the profiled bar opposite the outer surface; a second slot surface opposite the first slot surface and extending from the outer surface to the attachment end of the profiled bar, wherein the first slot surface of one profiled bar and the second slot surface of another immediately adjacent profiled bar define a slot; and a hardened layer disposed on at least a portion of the first slot surface of the profiled bar, wherein the hardened layer is disposed directly on at least a portion of the first slot surface of the profiled bar and the hardened layer is an outer layer.