3.
Reducers, if used, should be eccentric and preferably at the pump suction flange sloping side
down.
Figure 16:
4.
A centrifugal pump should never be throttled on the suction side.
5.
Suction strainers, when used. should have a net "free area" of at least three times the suction
pipe area.
6.
Separate suction lines should be used when more than one pump is operating from the same
source of supply. If it is not possible to have separate lines, piping arrangement shown in
is recommended.
Figure 17:
Suction piping design for large pumps
Large units taking their suction supply from sumps require special attention. A properly designed sump is
a must. The larger the unit, the more important these considerations become. A 3000 GPM pump should
be considered a large unit.
The following sketches will show the preferred pipe arrangement within the sump. Pipe should be located
near the back wall of the sump as shown in
18 and should not be subjected to rapid changes in direction of the flow pattern.
2.7 Piping - suction
18
Model 3415 Installation, Operation, and Maintenance Manual