Andritz Sprout-Bauer, Inc.

Ronald L Musselman

Wilhelm Mausser

Gregory R Kohler

Walter Writzl

William F Lahner, Iii

Josef Krasser

Franz Haider

Heinrich F Munster

Karl T Dahiqvist

Josef Muser

Alfred Lang

In an apparatus (10,100,300,400) for refining a low consistency fibrous slurry, which includes a plurality of refining zones (38,40; 188,128; 324,334; 411,413) within a casing, the improvement comprises providing a unique discharge flow path from each refining zone to a respective unique discharge line (56,58; 130,142; 308,310; 411,413) out of the casing, and means (57,59; 141,143; 344,346; 432,434) for differentially adjusting the flow rate in each discharge line. In accordance with the preferred embodiment of the invention, a divider (42,132,340) is provided between the casing and the rotor member, thus dividing the discharge between the two refining gaps, into two separate flow streams. The first and second gaps are monitored in any conventional manner. Under operating conditions, the flow control valves are adjusted for combined flow from the refiner casing as required by the production demands. However, the relative positioning between the two valves is adjusted until the refining gap measurements show equal gaps (within a pre-established tolerance) in the two refining zones.

Dual zone refiner with separated discharge flow control

Apparatus and method for the mechanical refining of high consistency lignocellulosic feed material in a frustroconical refining zone, by facilitating the backflow of steam generated in the refining zone through the upstream feed zone which, despite the backflow of steam, imparts outward force on the feed material sufficient for the material to enter the refining zone and pass therethrough, without blockage or flow interruption. This is accomplished by providing, immediately upstream of the frustroconical refining zone (46), a hybrid feed/grinding zone (104), which acts on the wood chips with relatively high refining intensity at low refining power, so as to reduce the size of the material and outwardly convey the material by centrifugal force into the frustroconical refining zone against the backflowing steam, but without generating steam in the hybrid zone. The hybrid zone receives chips from a feed screw (84) which preferably rotates at the same speed as the rotor (20) portion of the frustroconical refining zone and hybrid zone. The feed screw is shaped (e.g., as a ribbon screw) so that the chip material is easily 'handed-off' to the entry of the hybrid zone, while establishing an open channel (166) between the chip material and the shaft of the feed screw, for conveying backflowing steam away from the hybrid zone. First pressure control means (136) are provided in fluid communication with the backflow steam channel, for removing the backflowing steam from the refiner at a controlled pressure, thereby controlling the retention time of the material in the frustroconical refining zone (146).

Twin conical refiner with dual ribbon feeders

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Lewisburg, PA, United States of America

Ronald L Musselman