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Unusual Particle Counts Confusing
Doug McBride, Reliability TEAM Specialist, Temple
Inland
Assuming from the article that the test instrumentation is in
proper working order and calibrated correctly and this is occurring
in all or one of the units. You would first want to look at the
historical data to determine if there is a correlation to seasonal
changes,or has this happened in the past?
Verify correct labeling, oil flow path, and that the filter
has not failed. You might then want to look at personnel, has
there been a new technician assigned to pull samples, has he been
properly trained and followed correct procedures for taking oil
samples? Were two different technicians involved in taking the
samples?
Was the sample taken in the correct location? Sample bottles,
has a new shipment of bottles arrived? If so were they the correct
bottles? Certified super clean or just ordinary sample bottles,
were they mixed? Previous bottles with new arrivals?
If the problem were occurring in a specific unit, was the sample
taken during a period in the process when flow surge could have
hit the filter element and dislodged particles that went through
the bypass valve and migrated downstream? Is the filter sized
correctly to handle the flow surge without opening the bypass?
Has the flow surge been measured? Is there an in line flow meter
to determine the flow?
Has the system been worked on recently? Look at maintenance history
on the unit. Has the unit developed a leak between the downstream
side of the filter and the sampling port? One other thing that
you might want to look at is the filter itself, not that it has
failed but was it the same type and style as had been used previously,
could it have been changed and a different design type installed
inadvertently? Is the element itself of the same style and design?
This greatly effects the ability to withstand flow surge and to
hold onto particles.
Different manufacturers use different designs within their respective
filters. If the filter has not changed did the manufacturer make
a design change and fail to notify the end user of such? These
would be some things you would want to look at to help determine
the root cause of the abnormal downstream particle counts. One
other thing you might want to do is to plug in your portable filter
cart and circulate the fluid to clean it back up to allowable
cleanliness levels, pending resolution of the issue.
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