Installation Tips - Grundfos DDI 222 Instrucciones De Instalación Y Funcionamiento

5.4.1 Installation tips

• For non-degassing media with a viscosity similar to water, the
pump can be mounted on the tank (observe the permissible
suction lift).
• Flooded suction preferred.
• For media with a tendency to sedimentation, install the suction
line with filter (15i) so that the suction valve remains a few
millimetres above the possible level of sedimentation.
10i
6i
13i
15i
Fig. 7 Tank installation
With open outflow of the dosing medium or low
counter-pressure
A positive pressure difference of at least 1 bar must be ensured
between the counter-pressure at the injection point and the
pressure of the dosing medium at the pump suction valve.
• If this cannot be ensured, install a pressure-loading valve (7i)
immediately before the outlet or the injection unit.
7i
Fig. 8 Installation with pressure-loading valve
• To avoid the siphon effect, install a pressure-loading valve (7i)
in the discharge line and, if necessary, a solenoid valve (14i) in
the suction line.
Fig. 9 Installation to avoid the siphon effect
p
p _ 1bar
p  1 bar >
p
p -p _ 1bar
>  1 bar
p - p
1
2 1
2
1 7i
p
2
14i
• To protect the dosing pump against excessive pressure
build-up, install a relief valve (6i) in the discharge line.
• For degassing media:
– Flooded suction.
– Install a filter (15i) in the suction line to prevent the valves
being contaminated.
Fig. 10 Installation with relief valve and filter
• For line lengths above 1 metre a suction pulsation damper (4i)
may be required, depending on the flow rate.
4i
Fig. 11 Installation with suction pulsation damper
• For damper and line lengths above 3 metres and for flexible
pipework and line lengths above 5 metres, a pulsation damper
(8i) must be used to protect the system.
8i
Fig. 12 Installation with pulsation damper
p
10i
6i
15i
15