Monitoring of double-screen thickeners in the paper industry
Due to their complexity, plants such as double-screen thickeners present a challenge of their own in terms of maintenance. The number of slowly rotating roller bearings, including drive, press, pulling and regulating rolls and other components, can quickly reach 32. Considering that the availability of the entire plant depends on the functioning of each individual roller bearing, simple and inexpensive monitoring is required.
The common approach to condition monitoring of roller bearings is to collect vibration data (vibration measurement) at certain intervals. This data is then continuously analysed by experts on the basis of conventional methods such as the search for fault frequencies (e.g. outer and inner ring frequencies, etc.). Due to the high number of bearings, manual analysis by experts is very time-consuming and cost-intensive. Furthermore, the approach proves to be not optimal, as unplanned failures have occurred despite vibration measurement. Vibration measurement is only suitable to a very limited extent for monitoring slow-turning bearings, as the vibrations caused by the bearing damage are very small and often superimposed by operational vibrations and thus not detected. The prediction quality is insufficient, as roller bearings sometimes jammed already one week after the last measurement.
Advantages of the Senzoro system compared to vibration measurement
With the intelligent mobile Ultrasonic Condition Monitoring System from Senzoro, roller bearings can be monitored much more cheaply and reliably. The measuring process with ultrasonic sensors is very simple and can be carried out without specialist personnel after five minutes of instruction. The measuring times are shorter and the data analysis is carried out quickly and automatically on the basis of artificial intelligence. For the case study, this means that the duration of the measurement for 32 roller bearings, including evaluation and reporting, could be reduced from 8 hours to 1.6 hours (see graph).
Thus, a clear gain in productivity could be recorded. Last but not least, the analysis is of higher quality, as the Ultrasound Condition Monitoring System can also be used, for example, to calculate the remaining service life of roller bearings.
Author: DI Mag. Markus Loinig
Email: markus@senzoro.com
