Bertolini 74.1030.97.3, Руководство по эксплуатации, техническому обслуживанию и ремонту

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1-Feeder tank
2-Suction line
3-Drainage line
4-Pump
IN-Suction union (there are two unions, but one can be used if preferred - on the
side that facilitates the installation work)
OUT-Delivery union (there are 4 unions available, to be used as required)
D-Drainage union (there are two unions, but one can be used if preferred - on the
side that facilitates the installation work)
NOTE: If there is no tank in the application, connect the drainage line to the pump
suction side
4.5 Filtering and feeding circuit

The feeding circuit must be sized so as to avoid the risk of cavitation. Instructions on
how to size the feeding circuit are given in the next section 5.2 D. Always check to
make sure that the pressure does not drop below -0.2 bars for 750 rpm pumps or +2
bars for 1000 rpm pumps by positioning a pressure switch/pressure gauge behind
the pump suction union (shown in point 7 of the assembly layouts).

The pump feeding pressure must never exceed 5 bars.

The feeding line must be equipped with a filter , with 200 mesh filtration grade for
non-supercharged pumps. Filters with higher filtering grades can be used for
supercharged pumps. Whatever the case, the filters installed must not lower the
suction pressure indicated above. Consult section 5.2 B for further details. The
presence of the filter leads to a concentrated pressure drop which reduces the height
from which the pump can draw fluid. A filter with an adequate nominal flow rate must
be chosen to prevent this height reduction from being excessive. It is advisable to
use a filter with a nominal flow rate equal to at least 2.5 times the nominal flow rate of
the pump.

The diameter of the filter ducts must not be less than the diameter of the pump
feeding union.

The filter must be installed as near as possible to the pump and in an easily
accessed position. It must be inspected regularly, depending on the degree of
cleanliness of the water.

If water is supplied under pressure by a centrifugal pump, make sure that the flow
rate supplied is at least 1.5 times that of the pump.

Comply with the following instructions if the supply comes from a tank
–
The tank capacity must be at least four times the pump flow rate per minute.
– The pump feeding pipes must be positioned near to the bottom of the tank,