Method of and apparatus for making composite filter rod sections for use in filter tipping machines

摘要

A continuous tow of filamentary filter material is advanced past a rotary applicator which delivers metered but variable quantities of a second filter material (such as granulated or pulverulent charcoal) into successive increments of the tow. The tow and the delivered second filter material are thereupon draped into a web of wrapping material to form a filter rod which is sub-divided into sections of desired length. The density and/or the mass of the filter rod or of successive filter rod sections is monitored and the results of such monitoring operation are utilized to regulate the rate of delivery of second filter material so that the mass or density of the rod remains constant. The draw resistance of the filter rod or of filter rod sections can be monitored to generate signals which are used to regulate the rate of advancement of the tow toward the draping station and to thus maintain the draw resistance at least substantially constant.