|
Unusual Particle Counts Confusing
Dave Yunkers, Technical Specialist, Analysts,
Inc.
The particle counts had not been in question for the past three
years and suddenly over the last week the results are questionable:
This immediately implies something has changed! I would consider
the highest variables first (the human factors) and then look
for mechanical reasons.
1. The first review would be relative to personnel. Perhaps the
regular person is on vacation or someone new has been assigned
to collecting the samples. If so, was he/she properly trained?
2. Has there been a change in sampling supplies or provider
of the supplies? Are the containers of the proper cleanliness
requirements and being stored / handled properly?
3. Have the sample points or methods been changed?
4. Before arbitrarily changing the filters, check the differential
oil pressures. If the differential is high the filter may be the
cause. If the differential is lower than expected for a used filter,
the by-pass valve may be stuck open. This could also be a cause
for the erratic particle count results. In any case, check the
by-pass for proper operation.
5. If the post filter sampling point is not immediately after
the filter, inspect the lines and connections to insure there
are no leaks or loose connections. A leak may be drawing in contamination.
6. Review the laboratory testing procedures to ensure adequate
flushing of the particle counter between samples.
Following these considerations I'd carefully resample and evaluate
the results. If the conditions repeat, then change the filter
and resample after an appropriate operating interval as to allow
the new filter time to effectively affect the contamination levels.
See other responses
to this Readers Challenge.
Discuss
this topic on our message boards.
|
