Abstract: A powder-feeding method and apparatus according to which it is possible to provide one or a plurality of powder-feeding flows in which the powder is fed at a substantially constant rate which is of relatively small magnitude. A cone of powder is maintained substantially centrally of a disc which is rotated at a constant speed. A coarse scraper blade extends inwardly across the periphery of the disc into the cone of powder thereon substantially radially with respect to the disc so that the coarse scraper blade removes some powder on one side of the blade while leaving on the disc on the other side of the blade a layer of powder the depth of which is determined by the distance between the bottom edge of the coarse scraper blade and the top surface of the disc.

Abstract: This invention relates to improvements in and relating to filtering dust collectors.The improved filtering dust-collector is characterized by the provision of a number of dust-repulsing electrodes which are provided in close proximity to or even embedded within the filter material, said electrodes being adapted for being impressed with a single phase or a multi-phase high A. C. voltage.