Patent ID: 8048273

Claim:
A washer for washing and dewatering cellulosic pulp material comprising a rotary drum including a plurality of axial compartment walls separated by a predetermined distance disposed along said rotary drum defining a plurality of external axial compartments therebetween, a stationary cylindrical casing enclosing said rotary drum, thereby defining a ring-shaped space between said rotary drum and said stationary cylindrical casing, a plurality of axially extending seals having a predetermined width dividing said ring-shaped space into a forming zone for forming said cellulosic pulp material, at least one washing zone for washing said cellulosic pulp material, and a discharge zone for discharging said washed cellulosic pulp material, said predetermined width of said plurality of axially extending seals being larger than said predetermined distance between said plurality of axial compartment walls, at least two of said plurality of axially extending seals being arranged along the circumference of said rotary drum at different positions with respect to respective opposite axial compartment walls whereby upon rotation of said rotary drum said at least two of said plurality of axially extending seals contact adjacent sets of said plurality of axial compartment walls at different times.