Process For Manufacturing Reconstituted Tobacco Sheet Material In A Substantially Closed System

What is this patent about?

'253 is related to the field of reconstituted tobacco production, specifically addressing the efficient utilization of tobacco plant byproducts like stems, scraps, and dust. Traditional methods often involve costly separation and recombination steps, or result in a final product with a different chemical composition than the original tobacco material, leading to economic inefficiencies and potentially altered smoking characteristics.

The underlying idea behind '253 is to create a closed-loop system for producing reconstituted tobacco sheets that minimizes waste and maintains the chemical integrity of the original tobacco feedstock. This is achieved by carefully managing the soluble and insoluble components of the tobacco during the sheet-forming process, ensuring that they are all incorporated into the final product.

The claims of '253 focus on a system and method for producing reconstituted tobacco sheet comprising the steps of pulping tobacco plant parts with process liquor to form a slurry, forming a wet tobacco sheet on a moving wire carrier, removing process liquor from the wet sheet, transferring the wet sheet to a non-felt type fabric transfer belt, pressing the sheet to reduce process liquid, transferring the sheet to a dryer, and drying the sheet, wherein the process liquor and process liquid are maintained within a closed system.

In practice, the invention mixes tobacco stems, scraps, and dust with a 'process liquor' (water containing dissolved tobacco solubles and suspended insolubles) to form a slurry. This slurry is then processed through a series of grinders to reduce the particle size. The resulting pulp is diluted with more process liquor and fed onto a Fourdrinier wire to form a wet sheet. Crucially, the process liquor extracted during sheet formation is recycled back into the system, minimizing the loss of valuable tobacco components. The wet sheet is then transferred to a non-felt fabric belt for pressing and drying.

The use of non-felt fabric belts is a key differentiator, as these belts can be effectively cleaned with 'process liquid' (water and tobacco solubles), avoiding the need for fresh water and preventing dilution of the system. This allows for the recovery of nearly all tobacco solids, ensuring that the final reconstituted sheet has a chemical composition closely matching the original tobacco feedstock. The system also incorporates a clarification step to remove insolubles from the process liquid used for cleaning, further minimizing waste and maintaining a balanced chemical profile.