Drying Plant Dryer Roller Bearing Inner Race Fault
HD Envelope, a high-frequency technique, identified the source of vibrations in a drying plant’s dryer rollers, pinpointing a defect on the bearing’s Inner Race. This technique is particularly effective for detecting defects in components rotating at low speeds, providing greater certainty in diagnoses compared to traditional vibration readings.
A new client of ours in the paper industry asked us for help in identifying the potential problem with the dryer rollers of a drying plant consisting of approximately 45 rollers. A vibration monitoring system detected an increase in speed values (mm/s RMS) on a specific bearing.
Using HD Envelope, an effective high-frequency technique from SPM Instruments, we were able to precisely and confidently identify the source of the vibrations, shifting our focus from the bearing opposite the one where the highest vibration values were detected to the one where the actual defect was significant.
It should be noted that these bearings can only be replaced one at a time, a procedure that requires at least a couple of days and special preparation. A poor choice of bearing, or even worse, an unexpected failure, could lead to significant production downtime.
Although the defect observed in the images is significant, vibrations generated at speeds < 200 RPM are not always effectively and reliably distinguishable using speed or acceleration measurements detected by the most common monitoring systems.
The HD Envelope, however, allowed us to verify the presence of a significant defect on the bearing's Inner Race (BPFI), with amplitude modulation at the roller rotation frequency (RS).
Furthermore, the difference in values detected with this technique between healthy and defective bearings is much greater than that detected with vibration readings at speed, a characteristic that always allows us to have that extra certainty in the diagnoses issued, even for components rotating < 30 RPM (0.5 Hz).
Do you have similar applications and haven't tried it with vibrations considering low speeds? Believe us, it works!
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