Abstract: 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.

Abstract: A filter for a cigarette has an organic filtering portion defined by granules or fibres of active carbon and housed inside a cylindrical shell of plastic material; the shell is located between a portion of cellulose acetate, which is engaged orally by a user, and a cigarette portion, and has a bottom, contacting the portion of cellulose acetate and hermetically supporting a particulate trap for retaining fine particulate, and an end contacting the cigarette portion and closed by a plug of cellulose acetate.

Abstract: Filter plugs or sticks are directed from a filter maker onto a pair of conveyor rollers counter-rotating substantially in contact one with another at a point of tangency and furnished with equispaced peripheral flutes by which the single sticks are taken up and transferred from an infeed position to a release position. The flutes occupying a limited sector of each roller are connected selectively to a source of suction by an internal valve mechanism composed of a slide positionable to set the width of the sector, and a selector sleeve slidable axially between operating positions in which suction is generated across the sector through flutes spaced apart respectively at a longer pitch, and at a shorter pitch equivalent to half of the longer pitch.

Abstract: Filters for cigarettes are manufactured on a machine by which a web of activated carbon fiber fabric is decoiled from a roll, fed into a fragmentation device and broken up into filaments or particles. The fragments are gathered by a first unit into a continuous flow directed up and through the top outlet of an ascent channel into a further unit with a slidable and air-permeable aspirating belt such as will attract and retain the filaments or particles rising through the channel and shape them progressively into a continuous stream which is then released by the belt to the infeed of a unit equipped with a garniture section along which a strip of paper is wrapped around the continuous stream to form a continuous filter rod. Finally, the rod is fed through a rotary cutter and divided into sticks that will provide the single filter plugs for attachment to cigarettes.

Abstract: 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.