Goulds Pumps 3408 - IOM - Manual (Page 17)

3408 IOM 03/99
17
3
SUCTION AND DISCHARGE PIPING
The introduction of pumpage into a piping system which is
not well designed or adjusted may cause strain on the
pump, leading to misalignment or even impeller rubbing.
Since slight strain may go unnoticed, final alignment should
be done with the system full and up to final temperature.
Pipe flanges should not impose any strain on the pump.
This can be checked by a dial indicator. Any strain must be
corrected by adjustments in the piping system.
When installing the pump piping, be sure to observe the
following precautions:
Piping should always be run to the pump.
Do not move the pump to pipe. This could make final
alignment impossible.
Both the suction and discharge piping should be
independently anchored near the pump and properly
aligned so that no strain is transmitted to the pump when
the flange bolts are tightened. Use pipe hangers or other
supports at necessary intervals to provide support. When
expansion joints are used in the piping system they must be
installed beyond the piping supports closest to the pump.
Tie bolts and spacer sleeves should be used with
expansion joints to prevent pipe strain. Do not install
expansion joints next to the pump or in any way that would
cause a strain on the pump resulting from system pressure
changes. When using rubber expansion joints, follow the
recommendations of the Technical Handbook on Rubber
Expansion Joints and Flexible Pipe Connectors. It is usually
advisable to increase the size of both suction and discharge
pipes at the pump connections to decrease the loss of head
from friction.
Install piping as straight as possible, avoiding unnecessary
bends. Where necessary, use 45° or long radius 90° fittings
to decrease friction losses.
Make sure that all piping joints are air-tight.
Where flanged joints are used, assure that inside diameters
match properly.
Remove burrs and sharp edges when making up joints.
Do not “spring” piping when making any connections.
Provide for pipe expansion when hot fluids are to be
pumped.
DOWELING
Pump units may, if desired, (or required in
specification) be doweled on diagonally opposite feet.
This should not be done until the unit has been run for a sufficient length of time and alignment is within the
above alignment tolerance.
Fig. 11
Fig. 12