FTIR Spectrometers Used For On-site Lubrication Analysis

Jim Fitzpatrick, A2 Technologies Alan Rein, A2 Technologies

The manufacturer of the PAL series of portable Fourier Transform Infrared (FTIR) analyzers, A2 Technologies, announces new enhancements to this product line. The PAL systems quantify the level of water in these oils in the range of 50 to 5,000 ppm with accuracy of better than five percent.

This advance now permits the PAL systems to be as analytically effective as the gold standard Karl Fischer titration for measuring water in the aforementioned concentration range. The FTIR method is less time consuming, requires no hazardous or expensive reagents and can be performed on-site.

In addition to measuring the water level in lubricants, the PAL system immediately yields the amount of oxidation and nitration by-products present and the amount of antioxidation, antiwear and extreme pressure additives that remain in the lubricant. With this information, lubrication specialists and equipment maintenance personnel can make on-the-spot decisions about the condition of the lubricating fluid.

The PAL Series Microlab software has new features including the ability for users to overlay spectra for quick comparison of different oil samples and the ability to store the spectrum of unused oil as a reference for comparison to in-service oil as it ages. The Microlab software provides quantitative readouts for key lubricant parameters, allowing personnel to make immediate decisions about when oil needs replacing or refreshing.

FTIR has been an important technique for analyzing the condition of lubricants, but in the past, it was necessary to collect samples and then transfer them to an off-site commercial testing laboratory for analysis. Results might take days or even weeks to obtain, during which time the critical machinery could be subjected to wear from continuing lubricant breakdown.

The PAL on-site FTIR systems remove the need to analyze samples off-site and represent a significant advance for proactive maintenance of high-value equipment.

On-site FTIR also provides incoming oil quality assurance/quality control, in-service oil analysis and root cause analysis.


Figure 1. FTIR Spectrometer

Now an On-site Technique
FTIR spectroscopy has been a critical tool in lubrication analysis for more than 50 years, but breakthroughs in sampling, software and miniaturization means that this powerful tool is now available for on-site lubrication analysis.

FTIR Works with Existing Tools Viscosity
Viscosity is a key property of oil. FTIR can determine what is causing the change in viscosity, such as water ingress or oxidation.

FTIR is an ideal complement for minilabs that provide particle count, viscosity and dielectric measurements. When paired with both the chemical degradation of the oil and the accurate water measurements provided by the FTIR, the user has a complete on-site oil analysis capability.

Particle Counter
The FTIR can be used to understand changes in particle count caused by water ingress or increases in oxidation by-products.

Off-site Laboratory
The ability to quickly identify a problem on-site and take immediate action to remediate is a critical part of any predictive maintenance (PdM) program. The ability to monitor water in incoming oil or to catch a significant water leak and then test the remediation steps is invaluable.

Table 1. Predicted Water (ppm) in Turbine Oil (PAL System vs. Actual KF Results)

Low-level Water Detection
A2 Technologies has demonstrated that FTIR spectroscopic analysis using the PAL FTIR is as accurate and precise as the Karl Fischer method within the analytical range necessary for measuring water in a variety of different lubrications.

These on-site spectrometers can complete comprehensive water analysis in a matter of seconds with no sample preparation and no user training required.

Sample Measurement
The TumblIR sampling system handles oil samples easily and quickly with minimal cleanup. It consists of two windows that effectively sandwich an oil sample between them for easy oil analysis. A sample is squeezed onto the lower window and the top is lowered by a simple rotating action. After the analysis, the windows are easily rotated apart for cleaning. Cleaning is simple and easy. The system is immediately ready for the next sample. Only two drops of liquid are required for results.

Monitoring Additives
The role of additives is to enhance an existing property of the oil, suppress an undesirable property or add a property the base oil cannot provide. Examples of key additives are phenolic antioxidant, aminic antioxidant and antiwear or extreme pressure. The phenolic antioxidant is the most abundant antioxidant. The aminic antioxidant is the workhorse additive, doing most of the heavy lifting.

It has the ability to regenerate or recharge itself during the cycles of oxidation. The phenolic antioxidant, however, is a sacrificial antioxidant and one of its roles is to protect the aminic antioxidant. Monitoring these additives for depletion is a measurement of the ability of the oil to lubricate. When the phenolic and aminic antioxidants deplete, oxidation quickly compromises the ability of the oil to function as a lubricant.

The PAL Series measures both the antioxidant levels and the amount of oxidation present before a critical point is reached.

Oxidation is the primary mechanism of lubricant degradation. Lubricant base oils are primarily hydrocarbons. Oxidation of lube oils occurs when the hydrocarbon constituents of lube oil combine chemically with oxygen to form a wide variety of oxidation products such as aldehydes, ketones, alcohols and carboxylic acids.

FTIR is the proven method for determining the amount of oxidation in a lubricating oil and is currently a Work Item with ASTM.

About the Company

A2 Technologies manufactures portable FTIR spectrometers. For more information, visit www.a2technologies.com or e-mail vlopez@a2technologies.com.

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