Grundfos LS - 3.5.4 Inlet pipe if the feed line comes in different horizontal planes; 3.5.5 Inlet pipe with a horizontal elbow in the feed line

Wrong
1
2
3
TM040097
Inlet pipe resulting in air pockets
Pos. Description
1 Eccentric reducer
2 Air pocket
3 Pipe sloping down towards pump
3.5.4 Inlet pipe if the feed line comes in different
horizontal planes
Avoid high spots, such as loops, as they will collect
air and throttle the system or lead to uneven
pumping.
Correct
1
TM040095
Correctly mounted inlet pipe
Pos. Description
1 Eccentric reducer
Wrong
1
2
TM040094
Inlet pipe resulting in air pockets
Pos. Description
1 Eccentric reducer
2 Air pocket
3.5.5 Inlet pipe with a horizontal elbow in the feed
line
Make sure that the liquid flow is evenly distributed to
both sides of the double-suction impeller.
There is always an uneven, turbulent flow through an
elbow. See figure below. If you install an elbow in the
inlet pipe near the pump in a position other than
vertical, more liquid will enter one side of the impeller
than the other. This will result in heavy, unbalanced
thrust loads overheating the bearings, causing rapid
wear and reducing the hydraulic performance.
18
English (GB)