VLT
Vertical Process Pump
35 V1.090418
3. Thermal Growth
If there are thermal growth considerations on the piece of equipment, it is a good idea to get these
numbers so that they can be added to or subtracted from the graphical solution before the
equipment move is made, this is known as “Hot alignment”.
4. Soft Foot
The fact that your equipment could have a soft foot can affect the alignment readings that you
obtain. The soft 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).
To Next Page
Loading...
