1. Slow Speed Press Roll
©Bill Kilbey 2009

2. History Slow speed press rolls (60-180 RPM/1-3 Hz)
Normal vibration spectrums did not indicate a problem.
Vibration “thump” was felt in the extension pole in the 2 rolls in nip (felt/paper).
PeakVue waveform/spectrum data and circular plot made the defect clear.
Waveform Pk-Pk parameter in alarm

3. Multiple Normal Spectrums

4. Spectral Data Comments
The activity seen in the July reading is more active because the machine was running over 500 FPM. The other readings are in the 300 FPM range. When running at the higher speeds, a felt defects excite resonances in the frame.
Little periodic activity or indications of bearing defects.

5. Multiple Trends

6. Trend Comments
Note the Feet Per Minute was up, but the overall vibration is down
Waveform Pk-Pk is in “alert” (first level alarm).

7. WF Pk-Pk trend

8. PeakVue Spectrums

9. PeakVue WaveForms

10. Circular plot 3x TS impact at slower speed
9/16/09 - At higher speed, just one impacts is seen.

11. Circular plot comments
9/17/09 - At slower speed there are 3 impacts in each revolution. 3x turning speed is sometimes associated with a bearing loose on the journal or loose fit.
3 Distinct impacts/rev.

12. 1x Impact at higher speed

13. Recommendation made to repair
Decision to inspect in place during scheduled shutdown with roll manufacturer/rebuilder technicians
Lots of management attention (Better be right)
Replacement roll is $350,000 and 3 months delivery
No spare for this roll.
When the machine was shut down and the roll inspected….see next page

14. Worn/loose key and fit corroded/loose

15. Inspection/repair
Corroded and looseness in internal fit in bearing drive end.
Re-machined key way and new key.
New parts will be fabricated and installed at a later date.
Roll repair rep. stated “They (our customer) were very lucky”
I think it is just good data and analysis, not luck!

16. Follow-up PeakVue WF

17. Before/after circular plots