Hollow filter

Claim 1

The combination of a cigarette tobacco section; a filter immediately adjacent said tobacco section comprising a rigid tube extending the length of of said filter and defining a smoke passage aligned with said cigarette tobacco section for passage of an unfiltered portion of smoke said passage being of constant cross-sectional area throughout and being of a crosssectional size to have a draw resistance for controlling the amount of unfiltered smoke entering a smoker''s mouth for a given draw; a layer of compacted filter material circumferentially about said tube for receiving a second portion of smoke from said tobacco section for substantially complete filtration therein; and a cylinder of porous plugwrap paper about said layer of compacted filter material; and a cylinder of tipping paper joining said tobacco section and said filter together, said tipping paper having a plurality of perforations communicating the surrounding air with said layer of compacted filter material via said porous plugwrap paper, said perforations and said layer of filter material defining an air flow path having a draw resistance to complement said draw resistance of said smoke passage whereby for a given draw a desired amount of ventilation air and unfiltered smoke enters the smoker''s mouth.