摘要 |
A wall passageway, having openings therein only at opposite, inlet (14) and outlet (18) ends thereof, has a shaft (22) journalled therein. The shaft carries a screw thereon for moving shredded pulp through the passageway. The screw (24) is foreshortened, having a length less than that of the passage way, and causes inlet-admitted pulp to form into a continuously moving pulp plug. The plug, albeit having some porosity, comprises a gas seal within the passageway, and inhibits any migration of downstream gas from escaping to the atmosphere via the passageway and the inlet (14) thereof. In addition, a source (32) of oxygen or such gas as is inert to any downstream process is controllingly admitted into the inlet (14) to maintain an upstream pressure equal to, or greater than any downstream process pressure to insure against release of downstream gas into the atmosphere.
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