Tob. Reporter, 2008, 135-5, p. 58, ISSN.0361-5693
Filters for tobacco products
U.S. Patent 7,328,783 assigned to G.D. SpA, Bologna, Italy. Filters for tobacco products are manufactured by a device comprising a conveyor drum rotatable about a horizontal axis and furnished with peripheral grooves, each holding a leaf of paper material preassembled with a first filter element. The single groove is flanked by two tubular elements arranged symmetrically on either side of the drum, slidable axially between a first position located externally of the groove and a second position located internally of the groove, also by pushers slidable within the respective tubular elements and serving to direct second and third filter elements into contact with the end faces of the first filter element in such a way that the second filter element, which consists in a measure of powder or granular material deposited in each tubular element by way of a spool valve, remains interposed between the first and the third filter element. The leaf of paper material is engaged by a folder mechanism associated with the groove and closed around the two tubular elements to form a tubular wrap.