Goulds Pumps JC - IOM - Manual (Page 18)

Angular and parallel misalignment are corrected by means
of shims under the motor mounting feet. After each change,
it is necessary to recheck the alignment of the coupling
halves. Adjustment in one direction may disturb
adjustments already made in another direction. It should not
be necessary to adjust the shims under the pump.
The permissible amount of misalignment will vary with the
type of pump and driver. The manufacturer’s recommenda-
tions should be obtained and followed.
When the driver is to be mounted on the subbase in the
field, it is necessary to place the subbase with pump on the
foundation to level the pump shaft, to check the coupling
faces, the suction and discharge flanges for horizontal or
vertical position, and to make any necessary corrective
adjustments.
When the units are lined up cold, it may be necessary to
make an allowance for the vertical rise of the driver and/or
pump caused by heating. Goulds Pumps recommendations
should be obtained and followed.
ALTERNATE METHOD OF
ALIGNMENT
An approved method for putting the coupling halves in final
accurate alignment is by the use of a dial indicator. Check
alignment by straight edge, taper gauge or feelers as
accurately as possible by the procedure indicated above.
Bolt the indicator to the pump half of the coupling, with the
indicator button resting on the other half coupling peri-
phery, set the dial to zero, and chalk mark the coupling half
at the point where the button rests. For any check, top,
bottom, or sides, rotate both shafts by the same amount;
i.e., all readings on the dial must be made with button on
the chalk mark.
The readings will indicate whether the driver has to be
raised or lowered or moved to either side. After each
movement, check to see that coupling faces remain parallel
to one another.
With this method, accurate alignment of shaft centers can
be obtained even where faces or outside diameters of the
coupling halves are not square or concentric with the bores,
provided all measurements for angular alignment are made
between the same two points on the faces, and all
measurements for parallel alignment are made between the
same two points on the outside diameters. Gross deviations
in squareness or concentricity, however, may cause
problems due to coupling unbalance or abnormal coupling
wear and may need to be corrected for reasons other than
accomplishment of shaft alignment.
ALIGNMENT OF GEAR TYPE
COUPLINGS
Gear type couplings are aligned in the same manner as
outlined above. However, the coupling covers must be
moved back out of the way and measurements made on the
coupling hubs as shown on Fig. W9.
FACTORS THAT MAY DISTURB
ALIGNMENT
The unit should be checked periodically for alignment. If
the unit does not stay in line after being properly installed,
the following are possible causes:
l Settling, seasoning or spring of the foundation.
l Wear of the bearings.
l Pipe strains distorting or shifting the machine.
l Springing of the baseplate by heat from an adjacent
steam pipe or from a steam turbine.
l
Shifting of the building structure due to variable loading
or other causes.
l Loose nuts or bolts on the pump or driver assembly.
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JC IOM 5/08