Comparison Between Rotoscale & Solid Flow Feeder:
10.4 Conclusion
We should go for Rotoscale/multicore for coal dosing, kiln feed system and fly
ash feeding to cement mill in new projects.
S.N. Rotor Scale / Multicore Solid Flow Feeder
1 Very high accuracy of the system ( +/- 0.5
% on set feed rate)Lower accuracy of the system ( +/- 1.5
-2% of FSD)
2 Control range availability is higher ( 1:10) Control Range is Lower ( 1:5)3 Accuracy is not affected by the
influence variation in dedusting system
suction pressureAccuracy is affected by the dedusting
system suction pressure. Accuracy can
be achieved on constant draft of -20
to 30mmwc only. Hence , continuous
monitoring & control of draft becomes
essential for its accuracy.
4 Prospective Control software which
ensures correction prior to discharge of
the material, hence ensuring very high
short term accuracy and pulsation free
material feed.Follow up control is only available,
which is a simple control method.5 The system works on dual control
method. Here, rotor feeder and dosing
valve both are controlled to achieve the
set value. Hence, minimum deviation in
desired material fed.The system works on single
control method. Here, only dosing
valve is controlled to achieve the set
value. Feed variations are experienced
during filling cycle. Hence, deviation in
material feed is more.
6 Due to minimum deviation in desired
feed, the variation in Preheater draft is
less, only 5 to 6 mmWCDue to larger deviation in desired
feed, the variation in Preheater draft is
observed as high as 25 to 30 mmWC7 Due to minimum deviation in feed , the
bucket elevator can run at up to its peak
load , in case it is required.Due to higher deviation in material fed,
the bucket elevator cannot be run at its
full load capacity.
8 Online Calibration during operation with
the help of automatic control of the
gravimetric measurement through load
cell makes the system more reliable.Shall possible with check weighing with
its feeding bin. But as the feeding bin
capacity is too large, its least count
becomes more. Hence short accuracy
cannot be maintained with the SFF.