Pump Installation; Minimum Inlet Pressure (Z1) - DAB KVC series Installations- Und Wartungsanleitungen

8.1 Pump installation

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The electropump must be fitted in a well ventilated
place and with an environment temperature not
exceeding 40°C.
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Electropumps with degree of protection IP55 may
be installed in dusty and damp environments,
without any specific protection.
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It is always good practice to place the pump as
close as possible to the liquid to be pumped.
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The installation baseplate, provided by the
customer, if they are metallic they have to be
painted rust and corrosion. They have to be flat
and stiff enough to resist to short circuit forces
and avoid resonnance due to vibrations.
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Concrete basements have to be well solid and dry
before installing the pumps.
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A firm anchoring of the feet of the pump assembly
on the base helps absorb any vibrations created
by pump operation.
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The pump may be installed in either horizontal or
vertical position, as long as the motor is always
above the pump.
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Ensure that the metal pipes do not transmit
excess force to the pump apertures, so as to
avoid causing deformations or breakages.
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Use pipes with a suitable thread to avoid damage
to the inserts.
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The internal diameter of the pipes must never be
smaller than that of the apertures of the pump
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If the head at intake is negative, it is indispensable
to fit a foot valve with suitable characteristics at
intake.
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For suction depths of over four metres or with long
horizontal stretches it is advisable to use an intake
pipe with a diameter larger than that of the intake
aperture of the pump.
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Any passage from a pipe with a small diameter to
one with a larger diameter must be gradual. The
length of the passage cone must be 5 to 7 times
the difference in diameter.
−
Check accurately to ensure that the joins in the
intake pipe do not allow air infiltrations.
To prevent the formation of air pockets, the intake
pipe must slope slightly upwards towards the
pump.
ENGLISH
Fig. 3
positive slope towards
the pump for the
suction pipe
non-return valve
−
Interception valves must be fitted upstream and
downstream from the pump so as to avoid having to
drain the
maintenance. Do not run the pump with closed
valve on the plant.
−
If there is any possibility of the pump operating with
the interception valves closed, provide a by-pass
circuit or a drain leading to a liquid recovery tank.
−
To reduce noise to a minimum it is advisable to fit
vibration-damping couplings on the intake and
delivery pipes and between the motor feet and the
foundation.
−
If more than one pump is installed, each pump must
have its own intake pipe. The only exception is the
reserve pump (if envisaged).
8.2 Minimum inlet pressure ( Z1 )
(negative suction head pump)
To have good performances of the pump avoiding
cavitation phenomenon it is necessary to calculate the
suction lift Z1.
Fig. 4
Z1
17
secure the pump to the
basement by a solid and strong
installation
system when carrying
Hr
pb
NPSH
pV
out pump