| 摘要 |
A smoking article comprises a smoking material rod and, to one end thereof, a flow-impedance device comprising a rod-like element of foam or fibrous material which is or has been rendered impervious to the flow of smoke therethrough and one or more open-ended smoke-flow passages extending from one end to the other of the element, the pressure drop of the passage or passages being in the range from 40 to 200 mm, preferably 50 to 100 mm, water gauge and said device being enclosed in a wrapping permitting inward flow of ambient air into the device, which has air-conducting means whereby air flowing inwardly through the wrapping is conducted to the mouth end of the device, the device being effective to remove not more than 25%, preferably 20%, of the total particulate matter of the smoke. The passage or passages may be formed by a bore or bores in the material or by a capillary tube or tubes. |
