Fermenter Agitation
Fermenters usually require very good agitation, and that takes considerable
power. Photo of fermenters and drives.
A strong agitator shaft is required. Entry of the shaft into the fermenter
could provide a path for contamination. Also, the fermenter is held above
atmospheric pressure so the place where the shaft enters should not be
a place where air escapes.
Sketches of seals
If the shaft enters the top of the vessel and extends to near the bottom,
some support is required. The next sketch shows a bracket that is welded
to the vessel to hold a bearing in which the shaft turns. Also shown are
baffles. Without them, the contents would swirl, and power would be wasted.
Why would power be wasted ?
Various impellers may be used. Turbine impellers deliver power well
and assist aeration by shearing bubbles. Propellors provide predominantly
axial mixing. Turbines are most often used, but they may be in combination
with propellors.
Sketch of impellers
Baffle page from other presentation
Move on to Inspection
These figures are taken from a BASIC program written by Gregory Fieldson
for a term project in 1988.