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Horizontal End Suction Pump for Chemical Process, ASME B73.1-2001
Installation, Operation, and Maintenance Manual – CPP21
foot should be checked first and eliminated. This can easily be done by mounting a dial indicator on the base
plate indicating off the top of foot on the machine to be checked. Each foot in rotation is then checked by
loosening only the bolt with the rest of the bolts being tight. A soft foot check should be carried out when the
unit is stationary for safety reasons, and should be carried out on whole drive train. It should never be necessary
to shim under the pump mounting feet. Soft foot issues could indicate excessive piping loads transmitted to the
pump, or that the baseplate has been twisted, and is not grouted and mounted flat.
B. REVERSE INDICATOR ALIGNMENT GRAPHICAL ANALYSIS
On a sheet of graph paper, lay out the equipment that you are trying to align. You should use a scale that is
convenient to the size of the graph paper. The distances that are critical are:
1. Distance from where the first indicator rides on the pump hub to where the second indicator rides on
the motor hub. In the example shown below, this is 10-1/2 inches (266.7 mm).
2. Distance from where the second indicator rides on the motor hub to the center of the front motor feet.
In the example below, this is 2-1/2 inches (63.5 mm).
3. Distance from the center of the motor front feet to the center of the motor back feet. In the example
shown below, this is 5-1/4 inches (133.4 mm).
Figure 5.1 Example for reverse indicator graphical analysis.
The next step is to determine indicator sag. Set up your bracket arrangement on a pipe. Set the indicator at '0'
on top. Roll set up until indicator is at the bottom of pipe. It will read negative. In this example, it is found to be -
0.005 inch (-0.127 mm).
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