Abstract: Screening apparatus for paper making stock comprises a generally cylindrical vertical housing having the interior thereof separated by a cylindrical perforated screening member into a screening chamber and an annular accepts chamber on the inner and outer sides of the screening cylinder respectively. The feed stock enters an inlet chamber below the screening chamber tangentially, and special provision is made for preventing heavy reject particles from circulating around the bottom of the inlet chamber. For this purpose, the inlet chamber is provided at a position spaced circumferentially downstream from the inlet port, with an outlet port into which high specific gravity particles are carried by centrifugal force along with the carrying liquid. A conduit leads from this outlet port back to the inlet chamber in order to maintain a continuous flow through this conduit.

Abstract: Screen cylinders, and methods of making the same for use in removing contaminant particles from papermaking stock, have a seamless cylinder body and the openings or slots therethrough are formed by directing a focused laser beam at an outer surface while focusing the beam intermediate the outer an dinner surfaces to form an opening or slot with tapered walls. Wear bars may be applied to the inside surface as a bead of weld material. The seamless cylindrical body is formed by centrifugal casting or by cold roller extrusion.

Abstract: Apparatus for pulping a web of broke advancing downwardly thereto comprises an open tub having at least one generally vertical side wall wherein at least one pulping rotor is mounted for rotation on a substantially horizontal axis. A screw of an axial length substantially greater than the maximum axial dimension of each rotor is mounted concentrically on each rotor and extends horizontally therefrom into the interior of the tub to engage a web of broke entering the tub from above and thereby to draw the web into engagement with the associated rotor.