Most problems with rotary equipment stem from the drum being misaligned. When it is not set to the right slope or is not paralleled, problems may occur. When we align a drum, first we review the drawings to determine the design slope and locations of the tires, trunnion rollers, and complete unit. We measure the diameters of the tires and trunnion rollers. Then our crew will use a Non-Reflective total station Instrument that measures angles and distances (Electronic Distances Measuring) to perform the following alignment procedures:
Locate the centerlines of the trunnion bases
Determine the elevations of all the bearing surfaces
Determine the slopes of the bearing surfaces
With this information, we can determine where
to place each trunnion roller so the drum will be centered
over the bases.
In addition, we can determine the amount of shim required
at each bearing location to assure that the trunnion rollers
and drum will all have the same slope.
This will result in precise rotary drum alignment, with full-face contact of the tire on the
trunnion rollers and an even load distribution between the
By using the Non-Reflective
Total Station Instrument, we maximize the accuracy of our measurements.
The instrument measures directly to surfaces, it does not require
a prism, target, or scale to be held in place. Anytime a target
must be located and held by a human or stand, it introduces
additional chance for error in the measurement.
Once the laser in our instrument is directed onto the desired
surface, the instrument takes the measurement. It is not necessary
for the operator to read a scale or make a judgment call, and
record a value. The instrument measures the angle and distance,
then displays the values and saves them in memory.