Device for the fractionation of pulp

Claim 3

A device according to claim 1 wherein said inclined lower surface is angled at 30°-50° from the horizontal plane.

Claim 4

A device according to claim 1 wherein said laminae are ring-shaped and each has a radial width of approximately 2-10 times said distance between said laminae.

Claim 5

A device according to claim 3 wherein the radial width of said laminae is approximately 10-30 mm.

Claim 6

A device according to claim 1 wherein said chamber further comprises a bottom wall defining a second outlet therein and said central aperture of said screen member couples to said second outlet of said bottom wall of said chamber.

Claim 7

A device according to claim 1 wherein said inlet meet the upper portion of said chamber tangentially and in the direction of the rotation of said screen member.

Claim 8

A device according to claim 3 wherein said radical width is 3-5 times said distance between said laminae.

Claim 9

A screening apparatus for separating solids suspended in fluids comprising: a chamber having a generally cylindrical internal wall, an upper end and a lower end; inlet means provided in proximity to said upper end for feeding a suspension into said chamber in a direction substantially tangential to said internal wall; first outlet means provided in proximity to said lower end for discharging the suspension containing first solids from said chamber; a generally cylindrical rotatable screening member provided within said chamber for separating the suspension containing second solids finer than the first solids, said screening member having a plurality of substantially equally spaced circular laminae, each of said laminae having a downwardly inclined lower surface adapted to separate said first solids by the force of gravity and a centrifugal force generated by the rotation of said screening member; and second outlet means provided in proximity to said lower end of said chamber and coupled to the interior of said screening member for discharging the suspension containing the second solids from said chamber.

Claim 10

A screening apparatus for separating solids suspended in fluids comprising: a chamber having a generally cylindrical internal wall, an upper end and a lower end; inlet means provided in proximity to said upper end for feeding a suspension into said chamber in a direction substantially tangential to said internal wall; first outlet means provided in proximity to said lower end for discharging the suspension containing first solids from said chamber; a generally cylindrical rotatable screening member provided within said chamber for separating the suspension containing second solids finer than the first solids, said screening member having a plurality of substantially equally spaced circular laminae, each of said laminae having a downwardly inclined lower surface adapted to separate said first solids by the force of gravity and a centrifugal force generated by the rotation of said screening member; and second outlet means provided in proximity to said lower end of said chamber and coupled to the interior of said screening member for discharging the suspension containing the second solids from said chamber.

Claim 11

The screening apparatus according to claim 8 wherein said laminae are ring-shaped, each of said ring-shaped laminae having an outer circumferential portion oriented obliquely downward defining said downwardly inclined lower surface, and a plurality of cylindrical spacer members, each of said spacer members positioned between the adjacent laminae thereby positioning said laminae substantially in parallel with each other.

Claim 12

A screening apparatus for separating heavy solid particles from light solid particles contained in a suspension comprising: a chamber having a generally cylindrical internal wall, a closed upper and a lower end; inlet means provided in proximity to said upper end, said inlet means being adapted for feeding the suspension into said chamber and directing said suspension substantially tangentially to said internal wall to bring the suspension into a rotational motion along said internal wall; first outlet means provided in proximity to said lower end of said chamber and on the opposite side with respect to said inlet means for discharging the suspension containing heavy solid particles; a generally cylindrical screening member substantially concentrically provided within said chamber and rotatable about an axis of rotation, said screening member comprising a plurality of ring shaped laminae and a plurality of cylindrical spacer members, each of said spacer members positioned between the adjacent laminae thereby positioning said laminae substantially in parallel with each other, said spacer member including a plurality of apertures adapted for urging the suspension containing light solid particles into the interior of said screening member, each of said laminae having an outer circumferential portion including a downwardly inclined lower surface wherein the heavy solid particles between said ring-shaped laminae are moved outwardly against said lower surface by centrifugal force generated by the rotation of said screening member, said screening member further including a bottom end defining a central opening for discharging the suspension containing light solid particles; flow guide means provided in proximity to said upper end of said chamber for directing the flow of the suspension evenly onto the external surface of said screening member; and second outlet means provided in proximity to said lower end of said chamber and coupled to said central opening of said screening member for discharging the suspension containing the light solid particles.

Claim 13

A screening apparatus for separating heavy solid particles from light solid particles contained in a suspension comprising: a chamber having a generally cylindrical internal wall, a closed upper and a lower end; inlet means provided in proximity to said upper end, said inlet means being adapted for feeding the suspension into said chamber and directing said suspension substantially tangentially to said internal wall to bring the suspension into a rotational motion along said internal wall; first outlet means provided in proximity to said lower end of said chamber and on the opposite side with respect to said inlet means for discharging the suspension containing heavy solid particles; a generally cylindrical screening member substantially concentrically provided within said chamber and rotatable about an axis of rotation, said screening member comprising a plurality of ring shaped laminae and a plurality of cylindrical spacer members, each of said spacer members positioned between the adjacent laminae thereby positioning said laminae substantially in parallel with each other, said spacer member including a plurality of apertures adapted for urging the suspension containing light solid particles into the interior of said screening member, each of said laminae having an outer circumferential portion including a downwardly inclined lower surface wherein the heavy solid particles between said ring-shaped laminae are moved outwardly against said lower surface by centrifugal force generated by the rotation of said screening member, said screening member further including a bottom end defining a central opening for discharging the suspension containing light solid particles; flow guide means provided in proximity to said upper end of said chamber for directing the flow of the suspension evenly onto the external surface of said screening member; and second outlet means provided in proximity to said lower end of said chamber and coupled to said central opening of said screening member for discharging the suspension containing the light solid particles.