Patent ID: 6946072

Claim:
An apparatus for continuous washing of a fibre suspension with washing liquid, comprising an elongate rotor unit ( 1 ) that is rotatably journalled to rotate about an axis of rotation ( 5 ) in a pre-determined direction, an inlet section ( 2 ) having an inlet ( 10 ) for the fibre suspension and an inlet ( 12 ) for a washing liquid, an outlet section ( 4 ) having an outlet ( 16 ) for the accept and at least one outlet ( 18 ) for the reject, and a treatment section ( 3 ), comprising an annular, elongate treatment channel ( 24 ) for the fibre suspension, having an inlet end ( 72 ) and an outlet end ( 73 ) and being defined by a first, inner wall element ( 25 ) that forms part of the rotor unit ( 1 ) and is concentric with the axis of rotation ( 5 ) and a second, outer wall element ( 26 ) that is concentric with the axis of rotation ( 5 ) and located radially outside the first, inner wall element ( 25 ), wherein that the inner and outer wall elements ( 25 , 26 ) of the treatment channel ( 24 ) are impermeable to liquid, that the treatment channel ( 24 ) is free of constructional elements between its inner and outer wall elements ( 25 , 26 ), that the inlet section ( 2 ) has an inlet channel ( 11 ), into which said inlet ( 10 ) for the fibre suspension discharges, and which is concentric with the axis of rotation ( 5 ) and is annular, at least in the part closest to the treatment channel ( 24 ), and an annular inlet channel ( 13 ), into which said inlet ( 12 ) for washing liquid discharges, and which is concentric with the axis of rotation ( 5 ) and is located radially outside the inlet channel ( 11 ) for the fibre suspension, the inlet channels ( 11 , 13 ) being arranged to discharge into the treatment channel ( 24 ) at its inlet end ( 72 ) radially outside and adjacent to each other, so that an inner annular layer ( 74 ) of fibre suspension and an outer annular layer ( 75 ) of washing liquid that surrounds and is in direct physical contact with the layer of fibre suspension ( 74 ) are formed in the treatment channel ( 24 ), and that the rotor unit ( 1 ) is provided with a plurality of impeller vanes ( 27 ), arranged to cause the fibre suspension and the washing liquid to rotate about the axis of rotation ( 5 ) so that fibres in the fibre suspension move towards and into the outer layer of washing liquid ( 75 ) under the influence of the centripetal force.