| 摘要 |
<p>In order to obtain, during the smoking of a cigarette, each time the smoker draws,an amount of condensate which is more constant or is even less than heretofore, there is provided a cigarette filter unit having at least one membrane in the form of a screen positioned across the smoke-gas flow paths, the unit acting, while the cigarette is being smoked, as an internal bypass element. To this end, the spatial distribution of the openings in the membrane, and the cross sectional areas thereof, are accurately determined as to size and shape. The thickness of the membrane is between 10 and 150 .mu.m, the number of openings therein is between 500 and 25,000, and the cross sectional area of the openings is between 80 and 3,000 .mu.m2. Furthermore, an additional element providing at least one flow aperture whose cross section is at least 10 times larger than that of the largest opening in the membrane and/or the ventilating openings, is provided after the membrane, as seen in the direction of flow, extending between the interior and the exterior of the filter unit.</p> |
