A cigarette comprises a cigarette rod of smokable material enwrapped in a cigarette wrapper and a filter tip attached at one end of said rod by means of a tipping wrapper, which tip comprises smoke-filtration means and is provided at its periphery with at least one groove extending to the mouth end of the tip, the cigarette wrapper, at the region adjacent the tip, being depressed inwardly to provide at least one cavity which is in communication with at least one groove and that portion of the tipping wrapper which overlies the cavity permitting ingress of air into the same. The cigarette wrapper may be of heat-deformable paper and may comprise a proportion of thermoplastic fibres or filaments. The tipping wrapper may extend to the mouth end of the tip. The cavity may comprise at least one annular groove in the said cigarette rod or may be formed by a drawing down of the cross section of the rod, to provide an annular cavity, by means of an additional wrapper of heat-deformable or heat-shrink material.
A tobacco smoke filtration element having a first smoke-flow passage of filtration efficiency less than that of a second smoke-flow passage, the first smoke-flow passage being provided with a heat deformable material which, upon smoking of a smoking article incorporating such a filtration element, deforms and thereby obturates the first smoke-flow passage causing smoke to pass along the second smoke-flow passage and thereby to be subjected to a higher degree of smoke filtration after the first stages of the smoking cycle.
A smoking article having a valve system for closing off the flow of smoke to the user in response to an increase in temperature or humidity. The valve system includes a plastic body with a hollow valve chamber communicating with a smoke passage. A valve element is located in the chamber and is movable between a first position in which smoke from the smoking article is allowed to pass through the smoke passage and a second position in which the valve element closes the smoke passage thereby preventing smoke from passing therethrough. Expansion means are connected to the valve element and cause the valve to move between the first and second positions in response to the temperature or humidity of the smoke.
