General Mills started ultrasound measurements on a series of five cookers. The electric motor bearings are used to drive either side of a nip roll. They noticed that one set of bearings had higher readings than the rest. With what we know of comparative trends, it was a reasonable conclusion that these bearings needed more attention. The trend line was hovering around 50db but the bearings in question had readings of 69db and 64db respectively - roughly 5 times louder than the trend line.
The maintenance team replaced the bearings during the next scheduled downtime and the readings immediately dropped back in the 50db range. Upon examining the bearing the found the thickener dry and no oil left in the bearings.
Data trending and comparative analysis can often point out problems that would otherwise be missed.
Tip Provided By: Allan Rienstra, SDT Ultrasound Solutions