SILANORDNING FOER PAPPERSMASSA

摘要

A screening cylinder (20) for use in screening apparatus for paper making stock includes reinforcing skeleton structure comprising multiple bars (56) extending generally axially of the inside of the cylinder which are welded to relatively heavy reinforcing hoops (55) located at both ends of the cylinder and at a plurality of uniformly spaced locations along the length of the cylinder. Between each adjacent pair of these hoops is a plurality of circular rings of metal rod material arranged in closely spaced relation with each other and with the hoops to define a corresponding plurality of circumferentially extending screening slots. This screening cylinder is specifically designed for use in screening apparatus having a rotor comprising bars or vanes or air foil section moving in closely spaced, but non-contacting relation, with the radially inner surfaces of the axially extending bars (56) for the purpose of creating alternating positive and negative pressure waves effective to prevent plugging of the screening slots in the screening cylinder.