Abstract: A tobacco-smoke filter has a filter body comprising at least one intermediate section which is located between end sections, has a cross section less than that of the end sections and lies wholly within the outline of the latter sections as viewed axially of the body, and a porous wrap of sheet material which is pervious to volatile constituents of tobacco smoke and which bounds, with the said body, at least one space affording a path through which smoke can pass when the filter is in use and from which said constituents are removed fom the smoke by diffusion through the said sheet material, each of the said sections being made of filter material. Suitably the body is of generally cylindrical form and composed of cellulose acetate. Advantageously the intermediate section is integral with at least one end section.

Abstract: For shaping a component of a smoke filter, a rod of the material to be shaped and a heated former are relatively moved in contact with each other, in an arcuate path, in a direction transverse to the longitudinal axis of the rod, whereby an impression, for example an annular or helical groove, is produced in the rod by the former. For the said relative movement, the rod may be supported at the periphery of a rotor, while the former comprises a heated arcuate stator element or elements projecting inwardly towards the rotor. The rod may be turned about its axis during the relative movement, for example by a pair of rollers by which it is supported at the periphery of the rotor. A surface or surfaces bounding the impression, for example the bottom surface of a groove, may be sealed, during the shaping operation, so as to be smoke-impervious.

Abstract: The invention relates to a method for wrapping a continuous filter rod and producing tobacco-smoke filter sections which comprises feeding a wrapping strip of a thermoplastics film material, particularly a heat-shrinkable thermoplastics material, past an applicator for applying adhesive to the edges of the strip and, together with a filtering medium, to garniture means for wrapping the said strip around the said medium, which means includes a sealing station consisting of or comprising a cooled long folder, provided with a semicylindrical groove closely matching the rod size and of a length sufficient to permit setting of the adhesive to form a seam between the said edges, and feeding the wrapped rod thus produced to a cut-off device with guiding means for the cut-off sections. Preferably the adhesive is a solvent for the thermoplastics material.