Defibrator Aktiebolag

Johan G Johansson

A rotary grinding disc in an apparatus for refining fibrous pulp material, comprising a plurality of arcuate grinding plate segments disposed annularly about the disc and supported thereon by means of wedge-shaped tongues projecting from the segment plates and dovetailed into grooves of corresponding profile in the disc, the wedge-shaped tongues and dovetail grooves decreasing in width from an outer radial portion toward an inner radial portion, or vice versa, for wedging the plate segment into the disc. The plate segments may be additionally secured against disc placement by the effect of the centrifugal force during rotation of the disc by means of a peripheral ring surrounding the disc and engaging the wedged tongues.

Rotary grinding disc for defibrating apparatus

A rotary grinding disc in an apparatus for refining fibrous pulp material, comprising a plurality of arcuate grinding plate segments disposed annularly about the disc and supported thereon by means of wedge-shaped tongues projecting from the segment plates and dovetailed into grooves of corresponding profile in the disc, the wedge-shaped tongues and dovetail grooves decreasing in width from an outer radial portion toward an inner radial portion, or vice versa, for wedging the plate segment into the disc. The plate segments may be additionally secured against displacement by the effect of the centrifugal force during rotation of the disc by means of a peripheral ring surrounding the disc and engaging the wedged tongues.

Grinding apparatus in which lignocellulosic material such as wood chips is ground between a pair of grinding discs which rotate relatively to one another within a housing into which the material is advanced through a feed-in opening by means of a feed screw which rotates in a concentric sleeve extending between the central feed-in opening and an intake opening for the material. The feed screw comprises a series of inner screw flights mounted on a central shaft, which screw flights support and are enveloped by a series of outer ribbon-like screw flights. The inner screw flights are designed primarily to propel the material radially outwards towards the wall of the surrounding sleeve, whereas the outer ribbon-like screw flights are designed primarily to advance the material in an axial direction towards the central feed-in opening.

Conveyor device for feeding lignocellulosic material to a disc-type

Apparatus for relieving blockage of the pulp discharge passage in a cyclone separator included in a pulping system. The pulp stock is treated in an environment of superatmospheric steam and discharged together with the steam into the separator cyclone. The separated processing steam is evacuated from the cyclone while the steam liberated pulp stock is propelled through a throat which tapers towards the discharge valve by a screw conveyor whose flights are contoured to rotate snugly within the tapered throat. The discharge valve is controlled to maintain a predetermined rate of discharge and a predetermined superatmospheric pressure within the cyclone to allow evacuation of steam therefrom. The shaft of the screw conveyor is reciprocally mounted in the cyclone to allow the screw flights to yield in response to a predetermined excessive thrust resulting from compacted pulp stock blocking the throat, to provide a by-pass between the screw flights and the throat wall and thereby relieve the blockage. The invention may also include sensor means for controlling the rate of discharge in response to variations in thrust on the compacted pulp stock by the screw conveyor.

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Taby, Sweden

Johan G Johansson