Apparatus for treating webs of filtering material for tobacco product filters, particularly cigarette filters

摘要

Improved apparatus for treating a web of fibrous material, usually paper, to render it particularly suitable for making filter plugs for cigarettes, including at least one first pair of meshing rotating rolls provided with longitudinal grooves alternating with longitudinal ribs, which engage the paper and stretch it longitudinally in closely spaced successive narrow transverse areas to loosen and expose fibers without impairing the longitudinal continuity of the paper, and at least one second pair of meshing rotating rolls provided with circumferential grooves alternating with circumferential ribs, which engage the paper and groove it in a direction parallel to its travel while also stretching it transversely to further loosen and expose fibers without impairing the transverse continuity of the web. Preferably the apparatus also includes means for moistening the paper in advance of its passage through the rolls and for drying it after its passage therethrough. Means responsive to the tension on the web also are provided for adjusting the speed of the first pair of rolls relative to the second pair.