Abstract: An apparatus for providing a fluidized bed to effect the separation of a mixture of articles having at least a first density and a second density that is greater than the first density into separate groups. The apparatus includes an inclined trough which is supplied at an input end with either a fluidization medium, such as sand, or a mixture of articles from which a fluidized bed is formed by forcing gas upwardly through the bottom of the trough and through the fluidization medium or the mixture. In the case where a fluidization medium such as sand is used, the mixture of articles is introduced into the fluidized bed medium so as to be entrained therewith to effect separation as the articles travel in the direction of flow of the fluidized bed medium. Vertical oscillatory movement is imparted to the inclined trough to improve the separation and layering where the mixture of articles is fluidized, or to improve the density uniformity where a fluidization medium such as sand is fluidized as the bed.

Abstract: An apparatus for providing a fluidized bed to effect the separation of a mixture of articles having at least a first density and a second density that is greater than the first density into separate groups. The apparatus includes an inclined trough which is supplied at an input end with either a fluidization medium, such as sand, or a mixture of articles from which a fluidized bed is formed by forcing gas upwardly through the bottom of the trough and through the fluidization medium or the mixture. In the case where a fluidization medium such as sand is used, the mixture of articles is introduced into the fluidized bed medium so as to be entrained therewith to effect separation as the articles travel in the direction of flow of the fluidized bed medium. Vertical oscillatory movement is imparted to the inclined trough to improve the separation and layering where the mixture of articles is fluidized, or to improve the density uniformity where a fluidization medium such as sand is fluidized as the bed.

Abstract: 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.

Abstract: A gas is forced upwardly through a fluidization medium, such as sand, producing a fluidized bed which flows under the influence of gravity through an inclined trough. The separation of the side walls of the trough decreases in the direction of flow of the fluidized bed increasing the depth thereof. The apparent density of the fluidized bed is maintained substantially uniform, regardless of the increase in depth, by correspondingly increasing the pressure of the air forced through the medium in a manner corresponding to the depth thereof. A gas distribution plate beneath the fluidization medium having a higher resistance to the flow of gas than the layer of fluidization medium thereabove contributes to the maintenance of a substantially uniform apparent density in the fluidized bed despite variations in its depth.

Abstract: A fluidized bed apparatus for separating and sorting solid bodies of different densities.