Vibration Monitoring Keeps Paper Production
Rolling
Vibration analysis of a mission-critical
secondary centri-cleaner pump on a paper machine revealed that the overall
vibration trend, 1x turning speed
and
vane
pass, had been quickly rising for several weeks.
Production was alerted and tried adjusting the valves and
controls, but was not able to correct the problem.
A broken or cracked shaft was suspected because of the 1x
cpm amplitude changing. The high-end
data showing a rise in the noise floor
and the vane pass rising
revealed that cavitation was also a problem. After putting all of the
information together, the predictive maintenance team deducted that the
pump shaft could
have a plugged or restricted line.
On repair day, maintenance technicians removed the runner
and found a lot
of debris including a rusted bracket, several bolts and
a piece
of wood lodged in the impeller. The unit had been pumping with restricted
ports on the suction
side of the pump.
Wood Lodged in Pump Impeller
This repair was scheduled on a regular outage. Had the pump
failed, paper production would have come to a halt and production
loss cost alone would have exceeded $30,000.
The question that the team now faces is "Where did the debris
come from and is there any more still upstream?"
Submitted by Charles "Sandy" White, Blue Ridge Paper.
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