Processo e aparelho para preparação e expansão de lotes de tabaco

A tobacco expansion process and apparatus is provided to form a tobacco batch having a predetermined amount of tobacco, contact the batch with steam, load the batch onto a spool assembly, and impregnate the batch with an expansion agent. A double conduit apparatus is provided to load two simultaneously formed tobacco batches onto opposing sides of the impregnation spool. The tobacco batch is formed within a batch forming chamber comprising a vertically adjustable screen to accommodate different operating parameters and/or different tobacco types and/or forms. The batch is directed through a pneumatically separable zone to a precompaction and heating zone. The separable zone is defined by sequentially operating members, at least two of which form barriers to impede seepage of the expansion agent from the impregnating zone. In the precompaction zone the batch is precompacted against a permeable barrier, steamed, and then loaded onto a spool assembly for impregnation with an expansion agent.