Goulds Pumps 3196 i-FRAME - IOM - Manual (Page 38)

Installation
Fastening
WARNING:
• Only use fasteners of the proper size and material.
• Replace all corroded fasteners.
• Make sure that all fasteners are properly tightened and that there are no missing fasteners.
Suction-piping checklist
Performance curve reference
Net positive suction head available (NPSH
A
) must always exceed NPSH required (NPSH
R
) as
shown on the published performance curve of the pump.
Suction-piping checks
Check Explanation/comment Checked
Check that the distance be- This minimizes the risk of cavi-
tween the inlet flange of the tation in the suction inlet of the
pump and the closest elbow is pump due to turbulence.
at least five pipe diameters.
See the Example sections for
illustrations.
Check that elbows in general See the Example sections for
do not have sharp bends. illustrations.
Check that the suction piping The suction piping must never
is one or two sizes larger than have a smaller diameter than
the suction inlet of the pump.
the suction inlet of the pump.
Install an eccentric reducer be- See the Example sections for
tween the pump inlet and the
illustrations.
suction piping.
Check that the eccentric re-
See the example illustrations.
ducer at the suction flange of
the pump has the following
properties:
• Sloping side down
• Horizontal side at the top
If suction strainers or suction
Suction strainers help to pre-
bells are used, check that they vent clogging.
are at least three times the
Mesh holes with a minimum
area of the suction piping. diameter of 1/16 in. (1.6 mm)
are recommended.
If more than one pump oper- This recommendation helps
ates from the same liquid you to achieve a higher pump
source, check that separate performance.
suction-piping lines are used
for each pump.
If necessary, make sure that
—
the suction piping includes a
drain valve and that it is cor-
rectly installed.
Liquid source below the pump
Check Explanation/comment Checked
Make sure that the suction pip- This helps to prevent the oc-
ing is free from air pockets.
currence of air and cavitation
in the pump inlet.
Check that the suction piping —
slopes upwards from the liquid
source to the pump inlet.
36 Model 3196 i-FRAME Installation, Operation, and Maintenance Manual