Reordering Of Tobacco

What is this patent about?

'559 is related to the field of tobacco processing, specifically addressing the reordering of expanded tobacco after a heating process. Expanded tobacco, used as filler in cigarettes, requires a specific moisture content (12-15%) for optimal use in manufacturing. However, expansion processes often leave the tobacco hot and dry (4-8% moisture), necessitating a reordering process to increase moisture content.

The underlying idea behind '559 is to rehydrate hot, dry expanded tobacco in a controlled manner to prevent degradation and maintain its filling value. This is achieved by splitting the rehydration into two stages, separated by a cooling step. The initial rehydration brings the moisture content to an intermediate level, followed by cooling to near ambient temperature, and then a final rehydration to the target moisture content.

The claims of '559 focus on a method of reordering expanded tobacco that has been heated and has a low moisture content. The method involves a first reordering step to raise the moisture content to a first value, followed by cooling the tobacco, and then a second reordering step to raise the moisture content to a final, higher value.

In practice, the hot, dry tobacco exiting the expansion process is first sprayed with water to raise its moisture content to around 10-11%. This partially rehydrated tobacco is then conveyed through a cooling zone where air is drawn through the tobacco bed, facilitating rapid cooling via evaporation. This cooling step is crucial because it minimizes degradation and filling value reduction that would otherwise occur if the tobacco were immediately brought to its final moisture content while still hot.

This two-stage rehydration process with intermediate cooling differentiates from prior approaches that directly rehydrated the hot, dry tobacco to the final moisture content. By cooling the tobacco after the initial rehydration, the invention avoids the problems of filling value reduction and particle breakage. The cooling step also allows for more precise control over the final moisture content, as it eliminates the issue of partial evaporation of water due to the tobacco's residual heat.