VERFAHREN UND ANLAGE ZUR SICHTUNG VON GEGENSTÄNDEN, WELCHE GERINGE DICHTEUNTERSCHIEDE AUFWEISEN, MITTELS EINER FLOTATIONSSTRÖMUNG

A method and apparatus for sorting articles with small density differences utilizing a flotation stream. A separator is provided in which a flotation stream continuously flows through a trough and is used to effect the separation of a mixture of articles having small density differences into several groups. Each density group of the mixture of articles to be separated is introduced at the head of the flotation stream at a selected depth. In one embodiment, the flotation stream may be comprised of a fluidized bed which is created by forcing a gas upwardly through a fluidization medium such as sand. In another embodiment of the invention, the flotation stream may be formed from a liquid. Once the mixture of articles is introduced at the selected depth into the flotation stream near the head of the stream, since the density of the flotation stream is greater than the density of the articles, the articles of lesser density begin to ascend toward the top of the flotation stream while at the same time the articles are carried downstream by virtue of the velocity of the flotation stream. Articles having a greater density will be carried further downstream whereas articles having less density will ascend to the top of the stream at a point further upstream, thereby effecting a spacial separation of the articles based on their differing densities.