Bearing damage when stationary
In a petrochemical industry plant, a pump is on the list for periodic measurement. During the measurement rounds, the pump is already standing still for six months as this machine has been rendered redundant.
Because there was a long period without measurements, we asked to start it up in order to perform a measurement. During the measurements a problem with the bearings was discovered.
Determination upon measurement
During our measurements on this machine we measured a significant increase in vibrations at the pump. The figure below shows the envelopping of ping test point on the pump bearings at the impeller side.
Given the severity of the damage, an overhaul of the pump was advised.
All parts (inner ring, outer ring and the bearing balls) show damage in the form of corrosion because of the inactivity.
By starting the pump and still perform a measurement we were able to determine that this backup machine was not suitable to use. As a result, major problems in a critical situation (failure of a machine) were avoided.
The corrosion phenomena had a cause in steam leakage near the pump. This case demonstrates the usefulness of the regular exchange and checkup measurement of redundant and backup machines.