Installation
22 EN
04/2019
5.2 Pipes
5.2.1 Pipe
sizing
Suction lines which are too long have significant disadvantages:
•
Higher resistance which results in reduced suction
performance and a higher risk of cavitation.
A minimum length of double the inner diameter of the suction
flange must be planned for the calming section in front of the
suction flange.
For longer pipes, losses due to pipe friction must be taken into
account.
The nominal diameter of the pipe must be planned according
to the pump connections.
Do not exceed maximum flow speeds.
– Suction line: 1.5 m/s
– Pressure line: 2.5 m/s
5.2.2 Laying
pipes
Keep the suction and pressure lines as short and straight as
possible.
Avoid sudden changes to the cross-section and direction.
Lay the suction line below the water level.
Lay the suction line as follows to prevent air pockets from
forming:
– For intake mode: continuously falling.
– For suction operation mode: continuously rising.
If
clogging
is
possible, for example with straw or grass, install
a filter in the intake or the suction line.
Depending on the type of pump and system, install a non-
return valve as necessary.
Install a shut-off valve in both the suction and pressure lines.
Avoid
valves
which
close suddenly. Install a shock absorber
or air vessel if necessary.
Ensure that the suction line cannot leak.
Adapters with large nominal diameters and approx. 8°
extending angles should be used in order to avoid pressure
loss.
No stress or torque from the pipe system may affect the
pump.
