Abstract: An apparatus for production of dewatered and loosened biopulp, wherein precrushed raw biopulp is press fed by pistons (2) against a pair of counter-rotating press rolls (4, 5) between which the biopulp is dewatered. The pulp is then fed into a backpressure vessel (7) maintained at an overpressure, which prevents water from entering the backpressure vessel and remoistening the biopulp. The biopulp leaves the backpressure vessel through an air-tight compartment feeder (9) constructed like a revolving door. The press rolls include one of solid metal (5) and another (4) with a number of elastically mounted plates which can move radially in response to a radial load.

Abstract: A high-speed mill comprises a stationary ring-shaped head for clamping cutting plates thereto and an impeller borne inside the ring-shaped head, said impeller consisting of a rotor with fixed straight vanes and being adapted to bring about rotation of the material to be ground. According to this invention each cutting plate has at its cutting edge a plurality of successive chip-breaking cutting blades disposed in spaced relationship, and said cutting blades in adjacent cutting plates clamped in the head are laterally displaced relative to each other.