Patent ID: 8561807

Claim:
A magnetic drum separator for the separation of ferrous and non-ferrous materials from a material stream comprising: an outer shell that is rotatable around a central axis by a drive mechanism, said outer shell having a tubular length and a circular cross-section centered around said central axis; said tubular length is parallel to said central axis and said circular cross-section is perpendicular to said central axis; a pickup magnet that is an electromagnet positioned at a fixed location within said outer shell, extending along said tubular length, and having a cross-section perpendicular to said central axis in which a first end is closest to the inner circumference of said circular cross-section and a second end is located near said central axis; said pickup magnet comprising a core, at least one electrical wire wrapped around said core, and a backbar abutting said core at said second end; said core comprising a plurality of blocks, each block of different widths in a cross-section perpendicular to said central axis with the narrowest of said blocks at said first end and the widest of said blocks abutting said backbar such that said core has a cross-section perpendicular to said central axis that is an incrementally stepped tapered shape; and said pickup magnet powerful enough to produce a magnetic field suitable for separating ferrous materials from non-ferrous materials in the material stream.