Abstract: A drum flaker and knife therefor. A drum flaker comprises a drum for turning about an axis of revolution, a plurality of knife assemblies mounted to the drum, and a plurality of knives for mounting in the knife assemblies. The knives each have an elongate axis and comprise, on a first cutting side of the knife, at least two sets of cutting edges. The cutting edges of one of the sets alternate with and are radially offset from corresponding and respective cutting edges of the other of the sets.

Abstract: An apparatus for improving the pulping characteristics of wood chips in which a pair of closely operating rolls are provided for supplying compressive force to chips passed therebetween, at least one roll having an aggressively contoured surface for causing chips to crack in the thickness dimension of the chip as compressive force is applied to the chip.

Abstract: An apparatus is disclosed for separating material by length into first and second fractions containing, respectively, material longer than a specified length and material shorter than a specified length. The apparatus includes a plurality of generally parallel shafts having disks attached thereto. The disks are spaced on the shafts a distance approximately equal to one-half the specified length. Shaft diameters and shaft spacings are selected to cause material in the first fraction to remain supported by the shafts and to flow along the shaft surfaces from one shaft to the next adjacent downstream shaft, while material in the second fraction tilts and falls downwardly between adjacent shafts.