Tobacco smoke filter

摘要

Tobacco smoke filters are described which initially have flow passages of relatively low and relatively high pressure drop for the smoke passing through. Transversely to the, or each, flow passage of low pressure drop, a barrier is arranged, which is initially permeable to smoke but becomes blocked or clogged by the smoke passing through, so that the smoke initially flowing through the flow passage or the flow passages of low pressure drop causes the blocking thereof and the passage of smoke through the flow passage or the flow passages of high pressure drop is thus correspondingly increased.