Centrifugal Pumps Design and Application 2nd ed - Val S. Lobanoff, Robert R. Ross (Butterworth-Heinemann, 1992)

508 Centrifugal Pumps: Design and Application
etc. It is best in such cases to arrange for the various types of work to be
done separately, either sequentially or on separate shifts.
Heaters and Circulation. Some electric motors have base or winding
heaters that come on when the main power is deactivated. These can
cause undesired motor growth and can also magnetize dial indicators and
cause them to stick. It is usually desirable to get such heaters turned off
before starting the alignment. The same is true for any hot fluid or steam
circulation through pump or turbine.
Shading or Night Schedule. These are precautions more likely to be
needed with large elevated compressor trains than with typical pumps.
Nevertheless, it is worth mentioning that uneven sun heating can sometimes
affect alignment and cause inconsistencies during the job. The
usual ways of avoiding such problems are to erect a tarp sunshade or do
the work at night.
Installation of Pump on Pedestal. The pump foot and pedestal surfaces
should be clean and free of burrs.
Connection of Main Piping. Prior to connection of piping, stationarymount
vertical and horizontal dial indicators should be applied to the
pump at its coupling end, set to mid range, and zeroed. The pump suction
piping should then be connected, followed by the discharge piping. During
flange bolt tightening, the indicators should be watched, and any indicated
distortion should be kept less than 0.003 in. for each flange by
selective tightening of flange bolts. If this cannot be achieved, it may be
necessary to refit the pipe or use a dutchman. The latter is a tapered filler
ring inserted between the flanges, with a gasket on each side to occupy
the uneven gap. (See Murray [7] for more information on dutchmen.)
Coupling Surface Runout Check. This is sometimes necessary, but not
always. It should be done at face and rim measurement surfaces of any
coupling mat will remain stationary while the dial indicators rotate, contacting
these surfaces. If both coupling halves will be rotated in coordination
or while coupled, the surface runout check can be omitted. To do the
runout check, apply indicators mounted from a stationary point and rotate
the coupling while watching for deviations from zero start. If these
appear, mark their locations and set them away from quandrantal measurement
locations (top-bottom-side-side).
Soft Foot Check and Shim Recommendations. Soft foot should be
minimized to prevent machine frame distortion and inconsistent align-