Method and apparatus for the separation of materials using penetrating electromagnetic radiation

An apparatus for distinguishing and separating material items having different levels of absorption of penetrating electromagnetic radiation, comprising:

• (a) a pathway comprising means for conveying a plurality of material items randomly in a longitudinal feed direction from a trailing portion to a leading portion, the transverse dimension of said pathway being greater than the combined transverse dimensions of at least two of said material items,
• (b) an irradiation zone extending transversely over said leading portion of said pathway, and having a predetermined transverse dimension,
• (c) irradiating means spaced from said irradiation zone for continuously transmitting penetrating electromagnetic radiation into said irradiation zone in a sheet like pathway throughout said predetermined transverse dimension and through any of said material items conveyed through said irradiation zone,
• (d) a plurality of radiation detectors spaced transversely across said pathway for receiving radiation from said irradiation zone after said radiation has been transmitted through said material items in said irradiation zone,
• (e) signal analyzer means in electrical communication with each of said detectors for converting said radiation into electronic process signals, each process signal being commensurate with the amount of penetrating electromagnetic radiation passing through a portion of each material item which is different from any other portion of said material item, said signal analyzer selecting for processing those of said process signals which do not pass through irregularities in the bodies of said material items
• (f) separator means spaced in a trailing direction from said irradiation zone and transversely of said pathway and responsive to each of said electronic process signals independently of any other electronic process signal to actuate said separator means to selectively discharge all of said irradiated material items having one predetermined level of radiation absorption to one location, and all of said irradiated material items having another predetermined level of radiation absorption to another location.

A method of distinguishing and separating material items having different levels of absorption of penetrating electromagnetic radiation, comprising:

• (a) conveying a plurality of said material items in a random manner simultaneously and longitudinally along an elongated feed path;
• (b) establishing a transverse region across said feed path irradiated by a sheet of penetrating electromagnetic radiation;
• (c) irradiating said plurality of material items in said transverse region with said penetrating electromagnetic radiation;
• (d) simultaneously measuring the amount of penetrating electromagnetic radiation passing through each material item in said transverse region at any instant of time as said items are continuously conveyed longitudinally through said transverse region, to generate process signals;
• (e) obtaining a plurality of electromagnetic radiation penetration measurements through different portions of each of said material items;
• (f) selecting from said plurality of measurements a subset of measurements having greater transmission rates than others of the plurality;
• (g) clarifying each item from said subset of measurements for the item;
• and
• (h) simultaneously analyzing said process signals to cause said process signals to actuate means for directing said items to a different destination commensurate with the amount of said penetrating electromagnetic radiation passing through each of said corresponding material items.