The most common methods for initial detection of abnormal levels of wear debris in used oils include elemental analysis, ferrous density analysis (DR, etc.), particle counting and patch testing. For some users, because of the criticality of the application, all of these screening tests for wear metals are integrated into the routine test slate.

In such cases, when sampling is done correctly, it would be rare for the abnormal production of wear metals to go undetected. However, when only one or two of these methods are routinely deployed, there is a distinct risk that an incipient (early stage) failure condition may be missed.

The post Tricks to Classifying Wear Metals and Other Used Oil Suspensions appeared first on Tesibis.

The practice of transferring suspended particles to the surface of a membrane for analysis has been around for decades. It is perhaps the earliest method for inspecting solid contaminants and wear debris in a used sample of oil. It is of no surprise that these methods have enduring use today. In fact, some are the basis of recently adopted standardized methods by ASTM and ISO.

While membrane-based procedures for preparing particles for analysis can be time consuming and messy (usually involving the use of glassware and solvents), the benefits can be substantial compared to alternative methods. The main advantage is the ability to both quantitatively and qualitatively describe particle contamination, depending on the method used. As in the case of microscopic particle counting, you see what you’re counting and can confirm visually what appears to be a particle. You can also characterize particle type (e.g., dirt, wear debris, rust, fibers, etc.).

Because of the importance of these techniques to a modern and well-engineered oil analysis program, it seemed like a good time to review the options. There are actually eight different methods that are worth mentioning. Most have previously been covered in Noria publications, but a couple have not. We’ve used all but one of these methods in our failure investigation work here at Noria. A narrative of the methods is provided below and a summary that compares and contrasts them is shown in Table 1.

The post The Power of the Patch (Comparing particle analysis methods using membranes) appeared first on Tesibis.

The practice of transferring suspended particles to the surface of a membrane for analysis has been around for decades. It is perhaps the earliest method for inspecting solid contaminants and wear debris in a used sample of oil. It is of no surprise that these methods have enduring use today. In fact, some are the basis of recently adopted standardized methods by ASTM and ISO.

While membrane-based procedures for preparing particles for analysis can be time consuming and messy (usually involving the use of glassware and solvents), the benefits can be substantial compared to alternative methods. The main advantage is the ability to both quantitatively and qualitatively describe particle contamination, depending on the method used. As in the case of microscopic particle counting, you see what you’re counting and can confirm visually what appears to be a particle. You can also characterize particle type (e.g., dirt, wear debris, rust, fibers, etc.).

The post The Power of the Patch.  Comparing Particle Analysis Methods appeared first on Tesibis.