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US 4,362,172 AGranted
Cigarette filter
AssigneeBrown & Williamson Tobacco Corporation
InventorRobert R. Johnson
Life of this patent
Estimating the term…
Abstract
A filter for a cigarette includes a porous filter rod circumscribed by a non-porous wrapper and a tipping material having selected openings therein for allowing ventilating air to pass therethrough. Spacing members are disposed between the non-porous wrapper and tipping material to form ventilating air channels therebetween.
Claims8
A filter for a cigarette comprising:
- a porous filter rod of cylindrical configuration;
- a smoke impervious wrapper extending longitudinally along said rod from one end thereof and circumscribing said rod leaving flow-through opposed ends of said rod;
- tipping material extending longitudinally of and circumscribing said wrapper, said tipping material being provided with means permitting ventilating air flow therethrough;
- and,
- spacing means disposed between and non-unitary with said wrapper and said tipping material, said spacing means including a plurality of spaced parallel longitudinal members extending a preselected distance therealong defining ventilating air channels between said wrapper and said tipping material, ventilating air being the only fluid flowing through said channels when the filter is used in combination with a cigarette tobacco column during smoke draw.
2 more elements
Dependencies are inferred from the claim text.