Refiner filling piece having variably coated spacer-integrated bars

Abstract

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 spacer-integrated refiner bars having a bar portion and a spacer portion integrally formed with the bar portion. At least some of the spacer-integrated 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 spacer-integrated refiner bars may be tilted bars.

1 . 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 being mountable to the rotor or the stator, the refiner filling piece comprising:
 a base;   a plurality of spacer-integrated refiner bars having a bar portion and a spacer portion integrally formed with the bar portion; and   wherein at least some of the spacer-integrated refiner bars have a surface coated with a variable thickness coating.   
     
     
         2 . The refiner filling piece of  claim 1  wherein the variable coating has a coating thickness that varies over a bar height. 
     
     
         3 . The refiner filling piece of  claim 2  wherein the variable coating has a coating thickness that varies linearly over the bar height. 
     
     
         4 . The refiner filling piece of  claim 2  wherein the variable coating has a coating thickness that varies nonlinearly over the bar height. 
     
     
         5 . The refiner filling piece of  claim 2  wherein the variable coating begins at a point above the spacer portion thereby defining an uncoated lower portion. 
     
     
         6 . The refiner filling piece of  claim 2  wherein the spacer-integrated bar is tilted at an acute angle relative to the base. 
     
     
         7 . The refiner filling piece of  claim 2  wherein a leading surface of the spacer-integrated bar has the variable coating. 
     
     
         8 . The refiner filling piece of  claim 1  wherein the variable coating has a coating thickness that varies along a bar length. 
     
     
         9 . The refiner filling piece of  claim 8  wherein the variable coating has a coating thickness that varies linearly along the bar length. 
     
     
         10 . The refiner filling piece of  claim 8  wherein the variable coating has a coating thickness that varies nonlinearly along the bar length. 
     
     
         11 . The refiner filling piece of  claim 8  wherein the variable coating extends only partially along the bar length. 
     
     
         12 . The refiner filling piece of  claim 8  wherein the spacer-integrated bar is tilted at an acute angle relative to the base. 
     
     
         13 . The refiner filling piece of  claim 8  wherein a leading surface of the spacer-integrated bar has the variable coating. 
     
     
         14 . A refiner comprising:
 a housing;   a stator supported within the housing;   a rotor that rotates about an axis of rotation and cooperating with the stator to mechanically treat a pulp containing cellulosic fibers;   a first refiner filling piece fastened to the rotor; and   a second refiner filling piece fastened to the stator;   wherein each of the first and second refining filling piece comprises:   a base;   a plurality of spacer-integrated refiner bars having a bar portion and a spacer portion integrally formed with the bar portion; and   wherein at least some of the spacer-integrated refiner bars have a surface coated with a variable thickness coating.   
     
     
         15 . The refiner of  claim 14  wherein the variable coating has a coating thickness that varies over a bar height. 
     
     
         16 . The refiner of  claim 15  wherein the variable coating begins at a point above the spacer portion. 
     
     
         17 . The refiner of  claim 15  wherein the spacer-integrated bar is tilted at an acute angle relative to the base. 
     
     
         18 . The refiner of  claim 14  wherein the variable coating has a coating thickness that varies along a bar length. 
     
     
         19 . The refiner of  claim 18  wherein the variable coating begins at a point above the spacer portion. 
     
     
         20 . The refiner of  claim 18  wherein the spacer-integrated bar is tilted at an acute angle relative to the base.