3.4. Spigot capacity
Table 2 shows a comparison between the spigot capacity
obtained in this study and that specified in the DSM handbook
(Anon.). The spigot capacity from this study given in
Table 2 is in fact 80% of the actual spigot capacity. Normal
cyclone operation usually takes place with a spray discharge
at the spigot, hence, the introduction of the safety
factor. The value of 80% was chosen arbitrarily in this case;
the decision on this safety factor will be based on the
behaviour of the separation efficiency at around the transition
point to roping. This is the subject of further work.
The stability/sensitivity of the slurry flow through the spigot
close to the transition to roping should also play a role
in determining the above-mentioned safety factor.
The spigot capacity obtained in this study was slightly
higher than that given in the DSM handbook, even though
a larger cyclone (of 200 mm) was employed in the manufacturers
guidelines. Thus, depending on how the separation
efficiency is affected, the cyclone could possibly be operated
at higher spigot capacities than those in the manufacturer’s