APPARATUS FOR SCREENING PAPER FIBER STOCK

摘要

In screening apparatus for paper making fiber incorporating a cylindrical screen member provided with cylindrical screening perforations, each of the perforations is characterized by a concentric frustoconical inlet end portion having a maximum diameter at the inlet surface of the screening member which is substantially greater than the portion of the perforation of minimum diameter, the maximum diameter of these inlet end portions being such that adjacent such portions closely approach or intersect each other to define multiple ridges on the surface of the inlet side of the screening member.