Manufacture of tobacco smoke filters

Apparatus for manufacturing a filter rod containing a smoke-modifying agent comprising

• (a) means for moving a continuous multi-filament filter tow through a succession of treatment steps with the direction of movement coinciding generally with the longitudinal axis of the filter tow,
• (b) means for transforming the moving filter tow into a longitudinally oriented assemblage of filaments having individual filaments of the tow in substantial alignment,
• (c) converging means including a tongue device for gathering and compressing the longitudinally oriented assemblage of filaments to produce a longitudinally oriented filter tow with a rope-like configuration
• (d) rod-forming means adjacent to the converging means and having an inlet zone adapted to surround the termination point of the tongue device and to receive the longitudinally oriented, rope-like filter tow treated with said smoke-modifying agent,
• (e) conduit means associated with said tongue device and extending into the inlet zone of the rod-forming means, the portion of said conduit means extending into said inlet zone being in substantial longitudinal alignment with and positioned in the path of the moving filter tow so that the conduit means is substantially enveloped by the moving filter tow in encircling fashion, and
• (f) means for supplying controlled amounts of a smoke-modifying agent to the conduit means for application of said agent to the moving filter tow.

A method for manufacturing a filter rod containing a smoke-modifying agent which comprises

• (a) moving a continuous multifilament filter tow through a succession of treatment steps, the direction of movement coinciding generally with the longitudinal axis of the filter tow,
• (b) subjecting the moving filter tow to sufficient tension to produce a longitudinally oriented assemblage of filaments having individual filaments of the tow in substantial alignment,
• (c) moving the longitudinally oriented assemblage of filaments through converging means designed to gather and compress the assemblage of filaments thereby producing a longitudinally oriented filter tow with a rope-like configuration,
• (d) injecting a controlled quantity of a smoke-modifying agent into the interior portion of the filter tow by nozzle means positioned in the path of the moving filter tow at a selected location that is downstream of a point at which the filter tow has been sufficiently gathered and compressed by the converging means to envelop the nozzle means in substantially encircling fashion,
• (e) forming the filter tow treated with the smoke-modifying agent into a stable, continuous filter rod, and
• (f) cutting the formed continuous filter rod into suitable lengths for subsequent use in the manufacture of smoking products.