摘要 |
A fermentation apparatus (10) with a fermentation vessel (12) having a low speed stirrer comprising a shaft (14) with at least one stirring element (18) mounted thereon. First and second seal assemblies (30, 50), spaced axially from one another to define a chamber (64) therebetween, are provided to seal a gap between the shaft and a vessel aperture. An inlet (66) opens into the chamber for connecting the chamber to a processing gas, the first seal assembly (30) is located between the fermentation vessel and the chamber comprising a seat (32) mounted on the shaft for rotation therewith and a mating ring mounted (36) in fixed rotational relationship but moveably axially of the housing. A sealing face (44) of the mating ring is resiliently biassed into engagement with a sealing face (42) of the seat, and the sealing face has grooves (18) which provide separation of the sealing faces upon rotation of the shaft.
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