US 4,874,000 A · Method and apparatus for drying and cooling extruded tobacco-containing material

Abstract

Apparatus and a method for processing hot, moist extruded tobacco-containing materials as they are continuously extruded by drying the extruded material rapidly with microwave energy, and then cooling the extruded material rapidly so that the surface temperature of the extruded material is decreased below the bulk temperature to provide the extruded material with an adequately rigid and stable dimensionally structure that can be formed into a smoking article. Microwave drying provides substantially uniform drying without case hardening the material. Cooling may occur by passing air at high velocity, refrigerated air or presenting a partial vacuum across the advancing extruded material, or contacting the material with cold contacting members or a cryogenic bath. Conventional maker devices can be used for forming smoking articles from the dried and cooled extruded material. The invention is useful particularly to process foamed, extruded materials into smoking articles which can be used with conventioanl cigarette maker equipment to produce large quantities of foamed, extruded tobacco-containing smoking articles having properties substantially equivalent to those of a conventional cigarette.

Claims43

Dependent claims

A method for processing continuously extruded tobacco-containing materials, comprising:

drying the extruded material by passing it from the die of the extruder to and through a microwave resonant cavity energized by microwave energy, and propagating microwave energy from a source into the resonant cavity, wherein the microwave frequency is responsive to the resonant frequency of the moisture or other solvent to convert them to a gaseous product;
and
exposing the extruded material to said microwave energy to reduce the OV level of the extruded material to an OV level at about or below the equilibrium OV level for of the extruded material;
and
cooling the extruded material so that the surface temperature of the extruded material is decreased below the bulk temperature to provide the extruded material with a structure adequately rigid and stable dimensionally for forming into smoking articles.

2 more elements

A method of making an extruded, coherent, tobacco-containing, generally cylindrical smoking article having a density within the range of from about 0.05 to about 1.5 g/cc and a structure providing sufficient heat transfer area or sufficient residence time or both for the hot gases drawn towards the proximal end of the smoking article by a smoker to cool and to exit the proximal end at a comfortable temperature for the smoker, the method comprising the steps of:

(a) mixing together from about 5 to about 98 wt. % of tobacco particles having a particle size of up to about 5 mesh and an OV value of from about 3 to about 20%, from 0 to about 60 wt. % of a filler having a particle size of up to about 350 .mu.m, from 0 to about 50 wt. % of a foaming agent including any solvent or vehicle other than water, from about 2 to about 40 wt. % of a binder selected from the group consisting of cellulosic binders, natural binders, modified natural binders, synthetic binders, and mixtures thereof, and water to form a wet blend containing from about 15 to about 50 wt. % of water;
(b) extruding the wet blend from step (a) through a die to form an extruded material;
(c) drying the extruded material to reduce the moisture content to at about or below the equilibrium value;
(d) cooling the extruded material and lowering the surface temperature below the bulk temperature, thereby providing the extruded material with a structure adequately rigid and stable dimensionally for forming into smoking articles;
and
(e) forming the extruded material into smoking articles.

3 more elements

Dependencies are inferred from the claim text.

Method and apparatus for drying and cooling extruded tobacco-containing material

Life of this patent

Method and apparatus for drying and cooling extruded tobacco-containing material

Life of this patent

Abstract

Claims43