MRO Magazine

Tip: Simple, on-site fluid analysis techniques

Rehana Begg   

condition monitoring fluid analysis patch testing

The benefits of condition monitoring through fluid analysis can make the difference between maximizing your oil change-out intervals and making a call on whether your equipment is fit for service. Regular fluid analysis will detect the ingress of dirt, water, incorrect lubricant and process contaminants from the manufacturing environment and, moreover, prevent unnecessary wear on the equipment.

If you want complete information, send it to the laboratory. In 99.9 per cent of cases, the lab can provide the best analysis because they are equipped, they are trained, they are experienced and they follow standards. They can do the oil analysis in the best way possible.

However, there are readily available oil analysis kits – I see it used at some of the places I consult with. Some plants do their own standard testing or basic testing. From there, they may need more information and send it to the lab.

The other method I have seen onsite is low-cost patch microscopy or patch testing. This is good because maintenance personnel can see particles with a magnifier or a microscope. They would take a sample of oil from the gearbox, for example, pour it through a funnel and then it passes through a filter. They clean it up and look at it through a microscope to see what particles are in the sample. The test will give an indication of whether there are any iron or dirt particles in the oil. This is a rough test compared to the fine-tuned testing that an oil analysis lab can provide, but it provides experience and information that will help maintenance personnel determine whether a more sophisticated test is required.


Another first line of defence test is checking the viscosity – how “runny” is it? Of course, visual testing is automatic – one sees how dirty the oil sample looks. This is a more subjective test.

Other tests that can be used to direct maintenance decisions include testing acidity or alkalinity, soluble and insoluble contaminants, oxidation stability, or checking the anti-corrosion and anti-rust characteristics.

Keep in mind that unless the maintenance staff is trained on issues that can arise from contaminants, taking the appropriate preventive action for correcting each problem can be challenging.

This article is published in the April 2016 issue of Machinery and Equipment MRO.

The tip came from Liane Harris, Certified Ultrasound and Vibration Specialist, ECS2 Group Inc. Harris is a predictive maintenance specialist at ECS2 Group Inc. and trains reliability technicians on individual PdM philosophies, applications and best practices.


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