Smoking article mouthpieces

摘要

A cigarette filter element comprising at least one duct extending from one end to the other of the element, which element is operated on by a heated former moving relatively to it in a rotary fashion. The heated former serves to provide a cavity or annular groove through filtration material of the element. The cavity or groove also extends through a section of the duct to provide a ventilation channel. The duct at least one may be of a smoke-impermeable nature and may be provided by one or more bores or thermoplastic tubes.