Waste paper from the pulper is pumped under pressure into the inlet chamber, and the tangential entry design of the cleaner inlet allows it to convert the kinetic energy of the pulp slurry into a rotating mass within the cleaner. As the slurry rotates inside the cleaner, shear planes are caused by acceleration of the pulp slurry as it travles from the outside diameter of the cleaner radially inward the axis of rotation, where it is then diverted upward through the vortex finder out of the top of the cleaner. These shear planes tend to strip high-density particles from the pulp fiber.