Abstract: A filter for a cigarette has a porous filter rod with a channel extending longitudinally through the filter rod. The end of the filter at the tobacco column of the cigarette includes a partition having an orifice therethrough of a smaller cross-sectional area than the cross-sectional area of the channel to provide flow communication between the tobacco column and the channel. The partition further provides for the flow of smoke from the tobacco column into the filter wherein the smoke is diluted as it is being filtered by ventilation air entering the filter rod through an air permeable material circumscribing the filter rod.

Abstract: A filter for a cigarette includes a porous filter rod circumscribed by a non-porous or air impermeable wrapper, and ventilating air grooves embedded in the wrapped filter rod which extend from one end of the filter rod a preselected distance generally longitudinally thereof. The ends of the grooves are recessed a predetermined distance or depth inwardly of the end of the filter rod and communicate with radially extending open channels formed in the one end of the filter rod. An air permeable tipping material circumscribes the wrapped filter rod which provides a path for ventilating air flow into the grooves. Due to the air impermeable wrapper, the air flowing in the grooves is segregated from the smoke flowing through the filter rod so that ventilating air is the only substance flowing in the grooves.

Abstract: A filter for a cigarette has a porous filter rod with a channel extending longitudinally through the filter rod. The end of the channel at the tobacco column of the cigarette is closed by a smoke impervious wall having an orifice therein of a smaller cross-sectional area than the cross-sectional area of the channel to provide flow communication between the tobacco column and the channel. The filter rod can be circumscribed with an air pervious tipping material.