Abstract: Fibrous materials are processed to produce a homogeneous mass of fibres by using a series of clothed cylinders, the fibrous material having passed from one cylinder to another. The cylinders progressively have coarser teeth, alternate cylinders rotating in different directions and the peripheral speeds of the cylinders are progressively greater. At least one worker roller is arranged tangentially with respect to two adjacent cylinders to work the material by rotating in the same direction as the slower peripheral speed roller. The flow of air is created along the path of travel of the material to cool and assist in transporting the material by encasing the cylinders in fitting cover means.