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:
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 trunnion rollers.
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 person 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.