The filter should normally be operated at the highest vat
level design point. At maximum available drum
submergence (typically 30-40%, depending
upon filter design), the ratio of filtration time
to dry time is the greatest. This setting
provides for maximum filter through-put
for any given drum speed. The vat level
should be reduced only if:
1. Formed cake solids are thin and
gelatinous/slimy in nature. For
this type of slurry, lowering the
operating vat level will not
reduce the filter through-put
and/or the thickness of the
formed cake, but will assist
in producing drier discharged
solids.
2. The slurry has a high solids
concentration and forms an
excessively thick cake. For this type
of slurry, lowering the operating vat
level will reduce the filter throughput
and the thickness of the formed
cake. The solids will be discharged more
efficiently and at a lower moisture content