There is provided a method and apparatus for manufacturing filters for smoking articles. The method comprises providing hollow tubes (309) of filter material. Each hollow tube has an outer diameter and an inner diameter. The method further comprises providing filter inserts (205). Each filter insert (205) has a first portion having a cross sectional dimension larger than the inner diameter of the hollow tube. The method further comprises inserting each filter insert (205) into a hollow tube (309) of filter material. During inserting, the first portion of the filter insert (205) engages with the hollow tube (309) to retain the filter insert in the hollow tube.

The filter for cigarette product includes a mouthpiece end side-filter material and a front stage-filter material. The mouthpiece end side-filter material has a low air flow-resistance unit that is arranged in a part of a cross section from a front end surface to a rear end surface and having a relatively low air flow-resistance, and a high air flow-resistance unit that is arranged in the remainder of the cross section from the front end surface to the rear end surface and having a higher air flow-resistance than the low air flow-resistance unit. At least on the rear end surface of the mouthpiece end side-filter material, the low air flow-resistance unit is arranged only in one semicircular area, of two parts into which the cross section of the mouthpiece end side-filter material is divided.

An aerosol-generating article according to an embodiment of the disclosure includes: a tobacco rod having an outer circumferential surface surrounded by a wrapper; a filter rod having an outer circumferential surface surrounded by the wrapper, and including a segment including a structure supporting the wrapper in a transverse direction and at least one channel formed between the wrapper and the structure: and an airflow obstruction configured to obstruct an airflow of aerosol passing through the at least one channel.

There is provided a filter for a smoking article, the filter including a hollow tube of filter material having an outer diameter and an inner diameter. The filter further includes a flow restrictor disposed in the hollow tube. At least one cross sectional dimension of the flow restrictor is larger than the inner diameter of the hollow tube, such that the flow restrictor engages with the hollow tube to retain the flow restrictor in the hollow tube. There is also provided a smoking article including such a filter.

A filter device including a Bernoulli element is provided. The filter device includes a housing, a plurality of permeable membranes positioned in association with the housing to create a plurality of chambers in the housing, and a Bernoulli element positioned within one chamber, wherein the Bernoulli element causes airflow and pressure to vary within the one chamber when fluid comprising smoke is drawn into the filter device.

A filter for a smoking article comprises a mouth end filter segment and a rod end filter segment. The rod end filter segment has a passage extending longitudinally therethrough. The passage has a diameter of about 1.0 mm or greater. In one embodiment, the rod end filter segment is comprised of an infinite pressure drop material. In another embodiment, the rod end filter segment is comprised of a low pressure drop material having a hollow tubular element disposed within to define the passage with an inner diameter greater than about 1.55 mm. Air dilution means are disposed in one of said filter segments to admit ventilating air into the filter.

There is provided a smoking article comprising a filter. The filter comprises a hollow tube having an inner surface. The filter further comprises a flow restrictor disposed in the hollow tube, and adapted to divert at least a portion of the flow of mainstream smoke between an outer surface of the restrictor and the inner surface of the hollow tube. Furthermore, the filter comprises a retaining element disposed downstream of the flow restrictor, the retaining element having one or more openings. Each of the openings of the retaining element has at least one cross-sectional dimension that is smaller than the smallest cross-sectional dimension of the flow restrictor to prevent the flow restrictor from moving downstream of the retaining element. The flow restrictor is substantially spherical, at least one cross-sectional dimension of the one or more openings of the retaining element being smaller than the diameter of the flow restrictor.

A filter for a smoking article comprises a mouth end filter segment and a rod end filter segment. The rod end filter segment has a passage extending longitudinally therethrough. The passage has a diameter of about 1.0 mm or greater. In one embodiment, the rod end filter segment is comprised of an infinite pressure drop material. In another embodiment, the rod end filter segment is comprised of a low pressure drop material having a hollow tubular element disposed within to define the passage with an inner diameter greater than about 1.55 mm. Air dilution means are disposed in one of said filter segments to admit ventilating air into the filter.

An aerosol-generating article according to an embodiment of the disclosure includes: a tobacco rod having an outer circumferential surface surrounded by a wrapper; a filter rod having an outer circumferential surface surrounded by the wrapper, and including a segment including a structure supporting the wrapper in a transverse direction and at least one channel formed between the wrapper and the structure: and an airflow obstruction configured to obstruct an airflow of aerosol passing through the at least one channel.