Papermaking screen apparatus

Abstract

A screen apparatus includes a tank receiving a papermaking raw material; a screen partitioning the tank into a primary chamber and a secondary chamber; a papermaking raw material supply passage for supplying a papermaking raw material to the tank; a foreign material discharge passage for discharges the papermaking raw material containing a foreign material that does not pass through the screen to the outside of the tank; a papermaking raw material discharge passage communicating with the secondary chamber, and discharging the papermaking raw material passing through the screen to the outside of the tank; a cylindrical rotor body rotatably provided inside the screen, and stirs the papermaking raw material in the primary chamber; and a stepped stirring member provided on the side surface except for both end surfaces of the rotor body. The stepped stirring member is formed at a falling gradient with respect to a papermaking raw material flow.

What is claimed is: 
     
         1 . A screen apparatus comprising:
 a tank configured to accept a papermaking raw material;   a screen configured to partition the tank into a primary chamber and a secondary chamber;   a papermaking raw material supply passage that communicates with the primary chamber of the tank, and supplies the papermaking raw material to the tank;   a foreign material discharge passage that communicates with the primary chamber, and discharges the papermaking raw material containing a foreign material that does not pass through the screen to outside of the tank;   a papermaking raw material discharge passage that communicates with the secondary chamber, and discharges the papermaking raw material that passed through the screen to the outside of the tank;   a cylindrical rotor body that is rotatably provided in the primary chamber as the inside of the screen, and stirs the papermaking raw material in the primary chamber; and   a stepped stirring member provided on a side surface of the rotor body except for two end surfaces thereof,   wherein the stepped stirring member is formed to have a downward gradient with respect to a papermaking raw material flow.   
     
     
         2 . The screen apparatus according to  claim 1 , wherein
 the stepped stirring member includes a plurality of single stirring members, the single stirring member is a substantially crescent-shaped member in which a width of an intermediate portion is wider than two ends in a longitudinal direction thereof, the longitudinal direction of the single stirring member is substantially parallel to two end surfaces of the cylindrical rotor body, the plurality of the single stirring members is adjacently formed stepwise, and the adjacent single stirring members are provided so that a leading end portion of an upstream single stirring member with respect to a papermaking raw material flow relative to a rotational direction of the rotor body is located before a leading end portion of a downstream single stirring member relative to the rotational direction of the rotor body, and   a male screw is provided in the single stirring member, passes through a hole of the cylindrical rotor body, and is tightened and fixed by being screwed into a female screw located in the cylindrical rotor body.   
     
     
         3 . The screen apparatus according to  claim 1 , wherein
 the stepped stirring member includes a plurality of single stirring members, the single stirring member is a substantially crescent-shaped member in which a width of an intermediate portion is wider than two ends in a longitudinal direction, the longitudinal direction of the single stirring member is substantially parallel to two end surfaces of the cylindrical rotor body, the plurality of the single stirring members is adjacently formed stepwise, and the adjacent single stirring members are provided so that a leading end portion of an upstream single stirring member with respect to a papermaking raw material flow relative to a rotational direction of the rotor body is located before a leading end portion of a downstream single stirring member relative to the rotational direction of the rotor body, and   a male screw is provided in the cylindrical rotor body, passes through a hole of the cylindrical rotor body, and is tightened and fixed by being screwed into a female screw located in the single stirring member.   
     
     
         4 . The screen apparatus according to  claim 1 , wherein
 the stepped stirring member includes a plurality of single stirring members, the single stirring member is a substantially crescent-shaped member in which a width of an intermediate portion is wider than two ends in a longitudinal direction, the longitudinal direction of the single stirring member is substantially parallel to two end surfaces of the cylindrical rotor body, the plurality of the single stirring members is adjacently formed stepwise, and the adjacent single stirring members are provided so that a leading end portion of an upstream single stirring member with respect to a papermaking raw material flow relative to a rotational direction of the rotor body is located before a leading end portion of a downstream single stirring member relative to the rotational direction of the rotor body.