GB1299855A - Improvements in or relating to tobacco smoke filters - Google Patents

Abstract

1299855 Tobacco smoke filters MOLINS MACHINE CO Ltd 3 Dec 1969 [4 Dec 1968 27 June 1969] 57703/68 and 32625/69 Heading A2C A filter for cigarettes &c comprises a number of separate layers of granular, powdered or like material held between coaxial tubes of porous material, the arrangement being such that smoke passes radially through the tubes and granular material. In one embodiment, a filter plug 2, Fig. 1, attached to a cigarette 1 consists of porous paper which is folded, wound or otherwise arranged into a number of substantially concentric layers 3 separating the layers of granular material and is terminated at its ends by sealing elements 5, 6. The mouthpiece end of the plug is fitted with a conventional stub 7 e.g. of paper or cellulose acetate fibres. The element 5 is apertured at 11 to communicate with an axial channel 9 and the element 6 has channels 12 communicating with an annular channel 10 so that smoke is constrained to pass radially, as shown by the arrows, through the porous walls 3 and layers of granules. The channels 9, 10 may contain spacing elements, such as axially extending ribs, or porous material, and the porous paper 3 may be corrugated, knurled, or otherwise roughened to assist in holding the granules against displacement. The elements 5, 6 may be interchanged so that smoke flow is radially inwardly, and two filler plugs, sharing a common element 6 or 5, may be arranged end to end. A construction suitable for production as a continuous rod is shown in part-section in Fig. 4 in which concentric tubes 103 of porous paper, spaced apart by sets of concentric rings 105 of thick paper, are enclosed by a paper tube 102 and outer wrapper 101. Alternate sets of rings 105 have a band of paper 106 between the outermost tube 103 and the tube 102, and the other alternate sets have a central, non- porous stub 108 and are spaced from the tube 102 by dimples 107 in the latter. The rod is severed at the regions A-A. The Specification describes a machine for making such continuous rod, using a single web of porous paper on to which strips to form the rings 105, and the stubs 108, are secured at intervals by adhesive. Then, after application of the granular material to the web the latter is slit longitudinally into strips of graduated widths which are stacked one above the other and formed into the concentric tubes. A web of paper to which the spacers 106 are applied and in which the dimples 107 are formed is subsequently applied to form the tube 102, followed by the application of the outer wrapper 101.