The deaerators have to be opened from time to time, so that entered air can escape.
After approx. 5-7 min. circuit operation the 3-way tap is brought to position „filtration“
again.
The first water (approx. 30 sec.) should be used for rinsing of the pure water pipes.
Only hereafter the pure water inflow pipe is put in the pure water tank. The full capacity
of 6 m³/h is adjusted with the slide valve preceding the flow rate meter of the precoat
filter. The pump pressure before the flow rate meter should be adjusted to 1 bar above
filter resistance with the adjustment of the pump speed.
The minimum capacity shall not fall below 1000 l/h. The filter loss of head is readable
at the pressure manometers of the precoat filter. The filter loss increases with
increasing pollution. The adjusted capacity reduces, so that readjustment has to be
carried out at the slide valve. If a filter loss of head of approx. 3 bar is reached at a
capacity of approx. 2 m³/h and at full pump capacity, the filtration process has to be
interrupted, as otherwise the plant operates uneconomically.
IV 1.3.3. Backwashing of the filter plant
During backwashing, the precoat filter is backwashed shock-wise in reverse
direction, i.e. downwards. By shocking in batches (see annex 4) the solid filter layer
is separated from the cartridges and flushed out through the sludge outflow hose.
The precoat filter must be backwashed with pure water.
IV 1.3.4. Bachwashing process of the precoat filter
Turn the 3-way tap of the precoat filter to position „circuit“. Close slide valve
preceding the flow rate meter of the precoat filter. Switch-off precoat pump. Close
main ball valve of the 4-way fitting. Open ball valve of the sludge outflow hose at the
precoat filter. Open de-aeration taps of the precoat filter. Uncouple circulation hose
at the circulation outlet of the precoat filter and wait until the precoat filter is
emptied. Then connect the circulation hose again.
Close de-aeration taps and ball valve of the sludge outflow hose. Couple pure water
pump with the pure water pressure hose (which is coupled with the pure water outlet
of the precoat filter). Set 3-way valve of the precoat filter to position "Filtration" and
start pure water pump. The pump has to be operated with full capacity. If the slide
Attention
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