| 摘要 |
A tobacco product (10, 10a, 10b) such as a cigarette having a wrapped tobacco column (16) and a filter (14, 14a, 14b) of filter material located in end-to-end relation with the tobacco column to filter constituents of the mainstream smoke. Means (Figs. 1, 2, 3) to provide dilution of mainstream smoke from 25 to essentially 100% are provided for maintaining the filter material in a cylindrical rod-like outline. An outer wrap (20) which surrounds the filter extends from one end toward the other and a band of paper forming a second outer wrap (18) unite the filter coaxially of the tobacco column. The outer wraps are substantially non-porous and of an axial length relative to the length of the filter whereby the surface area of exposed maintenance means is between about25 mm2 and about 750 mm2. The maintenance means may be an inner wrap (22) of paper, with (Fig. 3) or without (Fig. 2) perforations, having a uniform porosity in the range of about 300 to 50,000 cc/min/cm2 at a pressure equivalent to 10 cm of water (Coresta units). |
