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Operation and maintenance manual for
Hydrotech Drumfilter HDF501-series
7..MAINTENANCE
7.1.Backwash.system
The most frequent reason for a malfunctioning rinse system is clogging of the
spray nozzles. Clogging is due to particles in the rinse water supply or e.g. to
biological growth in the rinse piping system.
The nozzles should be checked for clogging every week or as often as the
application requires.
7.1.1.Removing.and.cleaning.the.spray.nozzles
1. Set the safety switch to OFF and the selector switch to 0. If a backwash
pump not supplied by Hydrotech is used, make sure that the rinse water
supply is shut off.
2. Remove the lids on the side where the backwash pipe is located.
3. Check for clogged nozzles by observing if water cannot pass through.
4. Remove the bayonet nut by turning it ¼ of a revolution counter clockwise.
Be careful not to loose the rubber seal.
5. Clean the nozzle with compressed air or a plastic brush.
Never
use a steel
brush or steel pin, as this will damage the nozzle.
6. Assemble the nozzle in the reverse order. Make sure that the nut has come
to a full stop after tightened it ¼ of a revolution clockwise.
7. Set the selector switch to 0 and the safety switch to OFF
8. Open the main valve.
9. Put back the removed lid.
10. Set the safety switch to ON and the selector switch to AUTO
(see also section 5.1)
WARNING!
It is important that the bayonet nozzle nuts (see figure 7.1.1) are
reassembled correctly after cleaning of the nozzles. If a nut loosens, the
nozzle will fall out and the resulting water jet can destroy the filter cloth.
Figure 7.1.1d
Spray nozzle parts:
1
Bayonet nut
2
Nozzle tip
3
Rubber seal
4
Nozzle body
5
O-seal
2
1
4
5
3
!
