Infeed disc for disc-type refiners

Abstract

An infeed disc for a disc refiner has infeed passages which are circularly spaced by portions thereof which define spokes. The spokes and the passages have special characteristics. The center line of each passage is skewed with reference to the axial center line of the disc, in both an axial and a circular sense, and thereby curved, causing the passage to be essentially curved to provide a circular offset of the openings from the respective ends of each passage. The disc is further characterized by a non-radial skewed orientation of its spokes, the center line of each spoke being angularly inclined to a plane which is radial to and includes the central axis of the disc. The centers of the respective axially spaced infeed and operating surface portions of the spokes are offset one from the other, in a circular sense. The leading and trailing edges of each infeed passage at the operating face of the disc are also each respectively offset from the corresponding leading and trailing edges at the infeed face of the disc, in a circular sense, about the central axis of the disc. One wall surface of each spoke provides the leading wall portion of one of the passages, having regard to direction of rotation of the disc in use, and is distinguished by a longitudinally extended offset at the entrance end of the passage of which it forms a part. This offset is in the direction of disc rotation and creates an insuction effect as the disc rotates.