Abstract: The cooperating surfaces defining a pressing nip in a chip crusher are formed with specific patterns to treat the chips by fissuring to facilitate penetration by cooking chemical for the making of pulp for papermaking and the like. One of the surfaces is provided with a plurality of land areas separated by valleys, the land areas being substantially continuous and extending in the direction of movement of the surface as it passes through the crushing nip. The surface cooperates with the surface of a roll which defines the other side of the nip, the roll surface is provided with a plurality of teeth with the crown of each tooth defining a line preferably extending substantially perpendicular to the direction of movement of the roll surface through the nip.

Abstract: Materials such as wood chips are classified by thickness by feeding same through a chip outlet onto a rotating disc adjacent the axis of rotation of the disc, the disc cooperating with a housing to define a tapering passage terminating in a narrow, restricted outlet adjacent the periphery of the disc, orienting bars project from the disc and extend radially from the axis of rotation to beyond the chip inlet. A frusto conical chip orienting surface extends from the radial outward extremities of the orienting bars toward the outlet in a position traversing the path of material leaving the orienting bars.In one embodiment, an oversized outlet is provided, positioned trailing the orienting bars in the direction of rotation behind a substantially unobstructed trajectory of material leaving the orienting bars. In another embodiment, the oversized outlets are replaced by breaker bars that cooperate with cooperating breaker bars on the housing to shear positions of the material away.