Patent ID: RE39940

Claim:
A screen cylinder comprising: a generally cylindrical screening medium having a plurality of openings therethrough; a generally cylindrical structural backing plate for structurally supporting said screening medium and having a plurality of openings therethrough; and said screening medium and said structural backing plate lying concentrically one within the other and having respective opposed surfaces in engagement with one another at an interface therebetween whereby said backing plate structurally supports said screening medium; one of said screening medium and said backing plate having a plurality of circumferentially extending recesses formed in its opposing surface and opening at the opposing surface of the other of said screening medium and said backing plate at the interface thereof establishing communication between the respective openings of said screening medium and said backing plate; and a plurality of axially spaced projections spaced one from the other in the axial direction defining said recesses and projecting radially from one of said screening medium and said backing plate at said interface; the openings in said screening medium being elongated and extending in a generally axial direction substantially normal to the circumferential extent of said recesses.