Help Desk Software
    

Technical Bulletin: Varnish Report Updates

Varnish Potential Analysis - Report Upgrades

In order to provide the best analysis and recommendations of varnish test results, TestOil will be making some changes to reporting and alarming of several varnish test parameters.

Ultra Centrifuge: After reviewing many case studies, TestOil analysts have determined that there are instances when ultra centrifuge results as low as 3 are associated with operations issues due to the presence of degradation products associated with varnishing. Due to this knowledge, TestOil will be lowering the marginal limit for the Ultra Centrifuge test to 3 from the current limit of 5. TestOil will also be lowering the current critical limit for the Ultra Centrifuge test to 6 from the current limit of 7.

Membrane Patch Colorimetry: Our current limits for Membrane Patch Colorimetry (MPC) for mineral oil and PAO synthetic based fluids are not changing. However, these limits have been found to be too strict for phosphate ester based fluids, which can have higher test results without experiencing varnish related issues. Therefore, TestOil will be raising the limit for the MPC test for phosphate ester fluids only. The new marginal limit for phosphate ester fluids will be >30, and the new critical limit will be >40.

RULER (Mineral Oils): TestOil’s RULER alarms were set a number of years ago based on the data that was available at that time. That data consisted of results and case studies from a limited number of lubricants. As more data has been acquired from a vast variety of lubricants, it has become apparent that limits should be adjusted. TestOil will be adjusting limits to be better in line with recommendations in ASTM D4378 Standard Practice for In-Service Monitoring of Mineral Oils for Steam, Gas, and Combined Cycle Turbines, as well as input from end users. For single antioxidant formulations the marginal limit will be <=35% remaining active antioxidant, and the critical limit will be <=25% remaining active antioxidant. For two antioxidant formulations the marginal limit will be <=35% remaining of the primary antioxidant, and the critical limit will be <=25% remaining of the primary antioxidant.

RULER (Phosphate Esters): For phosphate ester samples TestOil will be changing how RULER test results are reported. For phosphate ester samples, phenolic compounds are a fluid degradation product, not an antioxidant additive. Instead of reporting the amount of phenols present as a percent of the amount of phenols present in new phosphate ester fluid, TestOil will begin reporting the area of the RULER peak produced by the in-service fluid. The area of the peak has a direct relationship to the quantity of phenolic compounds present; therefore the peak area will be a clearer indication of the level of degradation products present.

Questions? Contact TestOil @ 216-251-2510

Comments are closed.