Uniform tar delivery profile filter

A cigarette smoke filter element, comprising:

• an outer elongate annular cylinder of tobacco smoke filter materials having a higher resistance to cigarette smoke flow therethrough,
• an inner elongate hollow cylinder of microfine fibres which is supported as said cylinder by radially-inwardly located support means, microfine fibres in said cylinder thereof each having a diameter from about 0.5 to about 10 microns, said cylinder of microfine fibres having a thickness of about 0.05 to about 4 mm and a density of about 0.05 to about 0.3 g/cc, said cylinder of microfine fibres having a tendency to become clogged against further cigarette smoke passage therethrough by tar filtered from cigarette smoke passing therethrough,
• an axial cigarette smoke path radially inwardly of said hollow cylinder of microfine fibres having a lower resistance to cigarette smoke flow therethrough than said outer annular cylinder of smoke filter material, and
• tobacco smoke flow path directing means located at one end of said filter element for directing cigarette smoke from a cigarette to which the filter element is attached, only into said outer annular cylinder of cigarette smoke filter material,
• whereby cigarette smoke from the cigarette passes to the smoker along a cigarette smoke flow path of fixed length and cigarette smoke from the cigarette during smoking of the cigarette is caused to pass through a progressively longer flow path through said outer cylinder before passing through said inner cylinder into said axial cigarette smoke path as a progressively increased proportion of said inner cylinder becomes incapable of effecting filtration as a result of said clogging, thereby removing a progressively greater proportion of filterable materials, including tar, from the cigarette smoke as the cigarette is smoked.