GB1311437A - Production of tubes - Google Patents

Abstract

1311437 Making tubes BRITISH-AMERICAN TOBACCO CO Ltd 22 Feb 1972 [10 March 1971] 6465/71 Heading F2P In the production of a tube, at least one continous strip 1 of a fibrous sheet material is passed first through a flanged flat guide B which imparts a bowed form 1b to the strip; then through a first forming section C comprising a tapering funnel 5 and a pair of rollers 6, 7 which impart an inverted U form; then through a pair of frusto-conical rollers 8 with flanges 9 for supporting the edges of the U-section, then through an adhesive-applying section D comprising a guide 10 a levelling roller 12 and a stepped adhesive applying roller 14, then through a second forming section E comprising rollers 15 and 16 which bring the strip to the form shown at 1e. With this form the strip enters a heater section F comprising plates 17, 18 forming a tapering inlet 19 followed by a substantially cylindrical guideway. In section F the tube is subjected to a final sizing and shaping to circular cross-section 1f and the edges are sealed together in a smooth butt joint. Finally the tube is passed through a cooling section G which can be in the form of an annular aircooler (not shown). The tubing is preferably drawn through the above system and presented to a cutter (not shown) by a traction unit H comprising a pair of driven grooved belts 23. The rollers of the various sections may be driven from the belt drive or may be driven independently. In an alternative arrangement the edges of the strip may be pre-treated with a heat-activatable adhesive and the adhesive applying section omitted. Concentric tubing may be produced from two or more strips passed through a single apparatus or two or more units arranged in series. The invention can be used to form cigarette filter tubes from suitable paper and preferably two strips of different porosity may be used.