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Operation & maintenance manual, Drum filter HDF 12/16/20/24 -series
Figure 6.2 Hydrotech standard control cabinet, type PFC (option). (The control cabinet’s construction is in general adap-
ted to the respective application).
A. Motor protection pump
B. Fuses
C. Logic module
D. Contactor, pump
E. Control relays
F. Level relays
G. Frequency converter
H. Main power switch
Hydrotech control cabinet type PF has a simpler control system with a logic module.
6.2.1 Level differences
The maximum permitted difference
between the water level inside and out-
side the drum is 250 mm during normal
operation (see Figure 6.3). The recommen-
ded level difference is 100–200 mm. If an
even flow after the filter is required the
filter must be run with a small level dif-
ference.
The filter must be installed so that the level
difference in the event of operating distur-
bances under no circumstances exceeds
450 mm.
The filter must be run so that the level dif-
ference during normal operation does not
exceed 250 mm.
Prolonged operation with a greater level difference will significantly shorten the life of the filter
panels and other vital parts.
Figure 6.3 Maximum permitted pressure difference during conti-
nuous operation.