Example: Installation for expansion
Correct
Incorrect
This illustration shows a correct installation for expan-
sion:
1
1.
Expansion loop/joint
This illustration shows an incorrect installation for expan-
sion:
4.6.2 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 between the inlet
flange of the pump and the closest elbow
is at least five pipe diameters.
This minimizes the risk of cavitation in the suction in-
let of the pump due to turbulence.
See the Example sections for illustrations.
Check that elbows in general do not have
sharp bends.
See the Example sections for illustrations.
—
Check that the suction piping is one or two
sizes larger than the suction inlet of the
pump.
Install an eccentric reducer between the
pump inlet and the suction piping.
The suction piping must never have a smaller diame-
ter than the suction inlet of the pump.
See the Example sections for illustrations.
Check that the eccentric reducer at the
suction flange of the pump has the follow-
ing properties:
•
Sloping side down
•
Horizontal side at the top
See the example illustrations.
4.6 Piping checklists
32
Model 3700, 3703, 3710, 3700LF, 3700LFI API Type OH2 / ISO 13709 1st and 2nd Ed. / API 610 8/9/10/11th Ed. Instal-
lation, Operation, and Maintenance Manual
Summary of Contents for Goulds Pumps 3700
Page 2: ......
