Pressure strainer device

Claim 1

A pressure straining device for a pulp suspension comprising an inlet chamber for pulp to be strained, at least one straining cylinder bounding said inlet chamber and through which acceptable pulp is strained, at least one rotatable vane movable in said inlet chamber proximate the surface of said straining cylinder, said vane having a cavity extending therein, one end of which is closed, said cavity extending along the vane longitudinally and said vane having a slot leading into said cavity and facing said surface of the straining cylinder to admit unstrained pulp collected on said surface into said cavity, a collection chamber having means for isolating itself from said inlet chamber, said cavity of said vane communicating at the other end thereof with said collection chamber for introducing said unstrained pulp thereinto, a secondary straining cylinder concentric with said first screening cylinder, extending outwardly and below said first straining cylinder and forming a separating screen between said collection chamber and said inlet chamber to strain said pulp received from the cavity of said vane, acceptable pulp passing thru said secondary straining cylinder and moving upwardly to said inlet chamber for admixture with the pulp coming thereinto, and at least one secondary rotatable vane movable along the surface of said secondary straining cylinder to clean said surface of the secondary straining cylinder.