Impeller packing machine with pre-conditioning hopper

Abstract

An improved feed screw impeller apparatus primarily for use in an impeller bag packing system that is especially suited for filling bags with finely divided and aerated powders. The apparatus comprises an elongated cylindrical shaft having impeller blades extending radially therefrom at about the midpoint thereof and a plurality of feed screw flights of generally helical configuration, at least two such flights connected to said shaft on each side of the impeller blades in substantial coaxial alignment with the shaft. In one alternative embodiment of the invention there are four impeller blades and four helical feed screw flights, two on each side of the impeller blades and each terminating along an edge extending in substantial alignment with a different impeller blade. Another version of the novel impeller is employed in a packing machine also having a novel pre-conditioning hopper. The hopper comprises a fluidization chamber, the bottom of which is sealed by a dissemination pad which permits low pressure air to be percolated upwardly through the powder product. Continuous air percolation during bag filling combined with the disclosed impeller assures rapid rates of product flow enabling the user to obtain high weight accuracy, short fill times and a compactly filled bag. This version of the impeller is shown utilizing feed screw flights on only one side of the impeller, however either impeller embodiment may be combined with the pre-conditioning hopper.