Patent ID: 6767432
Filing Date: 2004-07-27
Classification: D21C,D21F

Abstract:
An apparatus for treating pulp, which apparatus comprises:an essentially elongated outer casing having first and second ends which are closed with first and second end plates, respectively; an inlet conduit, Pin, at said first end of said outer casing for introducing a fiber suspension to be treated into the apparatus; a fiber suspension discharge conduit, Pout, at said second end of said outer casing for discharging a thickened fiber suspension from the apparatus; and a filtrate discharge conduit, Fout, provided in said outer casing for the filtrate; wherein essentially at least between the inlet conduit and the fiber suspension discharge conduit the apparatus includes, (i) a filter surface having a substantially round cross section, and (ii) a cleaning member positioned inside said filter surface, said cleaning member comprising a rotating shaft, and at least one screw thread fixed to said rotating shaft for keeping the filter surface clean, and wherein the fiber suspension and filtrate discharge conduits for the thickened pulp and the filtrate, respectively, are provided with valves for controlling the operation of the apparatus, and wherein said valves are controlled in response to input power to the shaft, on the basis of an impulse from a previous process stage or a pressure difference prevailing over the filter surface.