cellulose pulp or recycled paper is defiberized , screened and pumped . initial defiberizing , separation of non - disintegrated material , final defiberizing and pumping of the defiberized pulp are performed at a consistency of 6 to 18 %, preferably 8 to 12 %. preferably all operations are performed at the same consistency . a defiberizing rotor is disposed in front of an impeller in the inlet of a centrifugal pump . a screen plate is mounted close to the defiberizing rotor . defiberizing elements are arranged on the other side of the screen plate to move close to the screen surface .