| 摘要 |
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. |
