Analyzing Water in Oil. Michael Stern and Larry Girdler, EMD Chemicals, Inc. High water content of lubricating oils negatively impacts the operation and longevity of the oils and the mechanical equipment components being lubricated. Water increases the oxidation rate of oils, thus prematurely using up the oils’ oxidation inhibitors.
1. Crackle Test. In the crackle test a drop of oil is placed onto the hot plate and observed. If there is no water in the oil, no “crackling” will be observed. Conversely if the oil does contain liquid water, the heat will cause it to change to the vapor stage creating observable bubbles in the oil droplet.
Upon dissolving water in oil, IR is absorbed by a water molecule, though the peak would have moved a bit because of the varied environment around the water molecule. As per the ASTM standard practice E2412, water is determined by matching the peak in the IR spectrum at about 3350cm -1 to the water concentration, as shown in Figure 6.
Lubrication oil testing follows industry standard protocols, including viscosity, particle analysis, lubricity and water content. Other contaminants may be tested for, but these are the main items. Viscosity (an oil’s ability to resist shear) is an indication of a fluid’s ability to lubricate efficiently within a particular temperature range.
The most precise method for determining the amount of free, emulsified and dissolved water in a lubricating oil is the Karl Fischer moisture test. When used correctly, the Karl Fischer test is capable of quantifying water levels as low as 10 ppm or 0.001 percent and should be the method of choice when more exact water concentrations need to be known.
Oil analysis is a preventive maintenance tool that uncovers fixable problems before they become catastrophic failures. An effective lubrication program with oil analysis can provide longer equipment life, detect early signs of contamination and degradation, reduce equipment downtime and ultimately save you money.
For over 40 years, the U.S. Lubricants’ OilChek ® Oil Analysis Program has provided high quality, state-of-the-art analyses of lubricating oil, fuel, coolant and industrial products. The highly automated program provides a thorough examination of your lubricating system complete with written recommendations. Our experienced technicians use the best testing equipment available to generate quality data in identifying the best reliability practices, increased production and operation cost ...
Allowable Limits for Water in Lube Oil. For cross head type engines water in LO to be less than 0.2%; take immediate action when the water content is between 0.5% to 1.0%; water content above this may damage the engine. For trunk type engines water in LO to be less than 0.1%; take immediate action when the water content is above 0.5% ; water content above this may damage the engine.