Encountered a technical blind spot
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I recently encountered such a problem: the shaft runout was 0.6, while the alarm threshold was ±0.5. The zero point was set at the midpoint of this runout value, which meant that the clearance between the main and auxiliary thrust bearings was 0.3 each. When an alarm occurred, it indicated that 0.2 of the babbitt layer in one of the shaft bearings had worn away, resulting in an increased shaft runout of 0.8. At this point, the runout value exceeded the specified range, which suggests that it’s time to replace the thrust bearings It’s not possible to replace the thrust bearing set just because of one alarm. Is it a problem with the interlock value settings, or are there blind spots in my understanding that I haven’t noticed?
The last edit to this post was made by The path to petrochemicals is long on 2017-4-28 at 14:53. It’s also possible that the bearing shells aren’t worn out; rather, it’s just the zero point that has changed. It’s worth checking whether the gap on the other end has decreased accordingly
Thrust bearings do wear out, but it’s not necessary to replace them just because 0.2 of their surface has worn away. Generally, the babbitt layer is about 2 mm thick, so losing 0.2 of that thickness isn’t a problem
There might be an issue with the alarm threshold settings.
The thrust pads do not need to be replaced. The key is to find out the cause of shaft play. Control the process operations properly. The lubricant pressure looks good. There should be no problem
First, when there is an opportunity to shut down the machine, check whether there is any zero-point drift at the measurement points. Then measure the shaft play again, and considering both the requirements for seal installation and the operating instructions for the unit, determine whether it is necessary to replace the bearings based on the actual shaft play of the unit’s rotor