The drum pulper system consists of a rotating steel drum aseembly. One end of the drum is a high-consistency zone where chemical impregnation and defiberizing are done. Reject material is separated from the fibers in the adjoining screening zone, and then discharged from the other of the drum when the recycled furnish is wetted and then repeatedlly dropped on hard surface. Gentle but effective shearing forces are created which fiberize the paper without disintegrating the contaminants.

A rubbing effect is added when a rolling motion is applied between the impacts. Ink, size, laminates, and hot melt substances are effectively loosened from the fiber. The stock collected in the bottom vat has been screened and only very small particals. Such as sand, can pass with the accept fibers. These contaminants can easily be removed later in the process.