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Setting up a Condition Monitoring Programme
Getting the most out of oil analysis
To
get the most out of your oil analysis programme, you need to appoint a leader who has:
• Ownership and champions the cause;
• Makes a public commitment to make it happen;
• Will gather the resources to sustain it;
• Will devote time
& effort to follow it through.
To provide the program with the proper foundation, six basic questions must be asked:
NB: Some of these steps can be performed simultaneously, whilst others must be done in sequence.
What can I get out of my oil analysis programme?
This is basically determined
by your reason(s) for beginning the programme in the first place. For example, you might want potential machine
failures to be caught early, you may want to save some money or you simply want to monitor your oil's health over
time.
What units do I need to sample?
Hydraulic systems? Critical gearboxes? Engines only? Everything?! This is probably
the toughest step of all. To make this task a little easier, try to fit your equipment into lists (e.g.
definitely want to sample / would like to sample / must sample). So, if cost is your
deciding factor, some units can be sampled less often or even not at all.
From where on the equipment do I take samples?
In some cases, this question won't be relevant because there is only one
sampling point on the unit. However, you do need to consider if it is a good sampling point that will provide a representative
sample. For example, oil taken from the bottom of a sump will contain sediment that has settled out over time and so
will not provide an accurate picture of what is happening in the working part of the machine. Similarly, sampling
from an inactive location on the unit may give you positive results, whereas in reality your machine could be on the verge
of failing and you just won't see it!
Consider installing a sample point in a better location (budget-allowing of course). Also consider safety when installing sample points, especially when dealing with high-pressure hydraulic systems.
How do I actually obtain the sample?
If you are using the drop-tube method, the best way is to use a vacuum pump
(available seperately or with the start-up sampling case from OCLS) which delivers the oil straight into the sample bottle
with no mess! However, there will be some units which don't allow such a method. Therefore, some investigative
work may be required to locate a suitable sampling point on the machine. Also, there's the option of contacting
the unit manufacturer for help or browsing the Internet.
Full instructions are available on request from OCLS regarding the proper method
for taking oil samples.
How often do I need to take samples?
In
order to work out your sampling frequency, you need to ask yourself what you want to find out and how fast it needs to be
found. Obviously, cost can also be a factor.
When
deciding on how often you're going to sample, you should think about the equipment history and the likelihood of it failing.
More frequent sampling gives much better data trending and also picks
up on possible failures or problems as they're happening. Bear in mind that failures can happen very quickly
and so if you think that one of your machines has a problem (for example it's generating a lot of heat/noise) you should
increase the frequency of your sampling. This will give you a better chance of detecting the problem before it's
too late.
If a sample is taken only once yearly, the
lab analyst will not have much data history to make a comparison to. In contrast, monthly sampling provides a 90% chance
of problem detection before unit failure.
What tests do I need on my samples?
The tests that are required depend very much on the type of equipment/machine
the sample came from. For example, diesel engine oils require an Infrared Spectroscopy test, whereas a gearbox
oil does not. OCLS can advise customers as to which tests would be most useful for each type of sample.
Answering
these questions should help you to formulate good strategies for your oil analysis programme. However, if you are unsure
about any of the issues raised here, please don't hesitate to contact us.
Oil Check can provide answers to these and other fundamental questions. Make your appointment to discuss your requirements in detail.Other areas of assistance include:
Providing advice and support with any auditing or other monitoring processes you are obliged to undertake which involve setting up or maintaining an advanced condition monitoring programme.
Combining Vibration &
Oil Analysis
When
oil analysis and vibration analysis are integrated within a programme, the weaknesses in one technology can be overcome by
the strengths in the other.
For example, whilst oil
analysis cannot detect resonance, vibration analysis is ideal for picking it up. On the other hand, while vibration
analysis has only mixed success in detecting wear of oil lubricated journal bearings, oil analysis is very good at detecting
the wear debris in the lube and checking the wear severity. This helps the customer to make the important decision of
whether or not they should continue to operate the machine. Also, when both methods detect the same problem,
the subsequent diagnosis and follow-up recommendations are rarely inaccurate.
"Our experience shows
that a strong, up-to-date vibration programme can be improved by closely combining it with a strong oil analysis programme.
The combined programme then becomes more than the sum of the parts."
Oil
Check Laboratory Services Ltd, Room 104N, Denison House, Hexthorpe Road, Doncaster, South Yorkshire, DN4 0BF
Our New
Website: www.oil-analysis.org
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Oil-Check. All rights reserved.
