Patent ID: 8293523

Claim:
An agitator for a fermenter, comprising at least one vertical agitator shaft, to which is fitted at least one agitator paddle, a drive mechanism which rotates the agitator shaft, the drive mechanism driving an upper end section of the agitator shaft, and a centering bearing for centering the lower end of the agitator shaft, wherein the centering bearing is designed to be releasable from the agitator shaft in such a way that the agitator shaft may be centered by pushing into the centering bearing and held in the centering bearing solely by the force of gravity on the agitator shaft, wherein the centering bearing has an insertion funnel and includes a centering section disposed below the insertion funnel, wherein the agitator shaft includes a stub shaft at its lower end section, the stub shaft rotatably mounted with a bearing so as to be rotatable relative to a rest of the agitator shaft, and wherein the stub shaft includes a coupling element which positively engages the centering section.