Page 52 - North American Clean Energy July/August 2019 Issue

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Grease is the Word by David Swanson
MOST LUBRICATION BASICS
are fairly well-understood in this day and age, and there are plenty of resources of documentation regarding lubricating systems and analysis. But there’s still one lubricant that remains a mystery to many – grease. Grease itself is a poor lubricant. e oil and additives held in place by the grease soap bers are the elements that actually perform the lubrication in a system.
Areas such as manufacturing environments, OEM formulations, correct sampling methods, and compatibilities give us a better understanding of the functionality and necessity of grease analysis in lubricated equipment.
Grease Manufacturing Causing Complications
e manufacturing process for grease requires
high temperatures and pressures, and accurate applications, which cause complications during manufacturing. e tests designed to qualify grease from the manufacturing environment were designed decades ago, mainly to ensure quality. However, they were not speci cally designed to encompass qualifying grease for use in the eld.
Not All Greases Are Compatible
To make the scenario more complicated, most OEM’s specify three parameters: National Lubricating Grease Institute (NLGI) grade,
soap type, and (sometimes) a base oil viscosity requirement. Grease manufacturers have identi ed formulations. While these three parameters may
be identical, the actual formulations could be signi cantly di erent. Not all greases are compatible – even greases of the same soap composition may
be incompatible with each other. In extreme cases, this can result in a complete loss of lubrication in the component, and, ultimately, equipment failure.
Grease Sampling vs. Oil Sampling
Collecting an accurate, representative sample of your grease – to send in for analysis that provides a valuable maintenance recommendation – can be challenging; it’s not as simple as oil sampling. Poor sampling techniques and processes can give you limited information, or a false sense of security when there could, in fact, be a catastrophic problem.
e sampling processes of grease lubrication and oil lubrication are di erent. Grease is designed to release the lubricating oil charge with the soap holding it into the area where the lubrication is
required. As a result, the grease in the compartment will most likely be extremely non-homogeneous. Collecting a grease sample from the incorrect location (for example, the outer surface of your component) may not be representative of the grease next to the area being lubricated. Sending
in an incorrect, non-representative sample can mean receiving incorrect analysis results and maintenance recommendations.
To help collect a representative grease sample, some uid analysis laboratories provide customers with cost-e ective, easy-to-use sampling devices and other materials used to extract grease from the system. ese sampler devices are included in each type of sample kit. ey come with shipping tubes and labels for easy sampling and submitting to the laboratory.
Why Test?
It all comes down to cost. Grease is signi cantly more expensive than an equivalent lubricant. Accurate grease analysis is a major value add when it comes to maintenance, given that grease-lubricated systems are designed to last extensively longer
than oil-lubricated systems. is means there’s a nancial gain from gathering e ective and actionable maintenance recommendations from the results of your grease analysis.
Grease Testing and Analysis
Grease testing and analysis provides valuable insight into grease performance and integrity, including reliability-centered areas like wear, consistency, contamination, and oxidation.
Performing the maintenance actions recommended after grease is analyzed will result in: Minimized unplanned repairs; Decreased downtime; Extended machine life.
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