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Scientific American April 9, 1881 woodcut of a
Electric Middlings Purifier
Atlantic Mills, Brooklyn, N. Y. installed in May, 1880.
Middlings, bran, and flour dust in whatever combination—is received at the further end, and passes slowly under the rolls about two inches below. The agitation of the sieves causes the bran to rise to the surface, whence the light particles leap to the rolls and cling thereto until brushed into a shallow gutter placed in front of each roll. Meantime the heavy and electrically rejected middlings descend by gravity and pass through the bolts in the order of their fineness. Traveling brushes constantly sweep the bran from the gutters into the bran receiver on the left side of the purifier, in which is seen the spiral conveyor. By the time the last line of rolls is reached the material has been successively diminished by the abstraction of the bran and the screening out of the several grades of middlings, until only a trifling quantity of heavy refuse (if there be any) is left to pass over the tail of the purifier into the spout provided for it.