Measuring air contamination levels in your lubricants is extremely important because, should levels go above 10%, problems including oxidation and loss of compressibility could occur.
Luckily, there are several tools that can be used to measure air quantities in oil, and they should be used on a regular basis for best practice.
One of the most popular tools for measuring air content in oils is a device that can measure the amount of air within hydraulic lines. This particular tool creates a vacuum in the oil sample, which separates dissolved and entrained air from the lubricant and then the harvest is measured against the original amount of oil, thus enabling the user to determine the percentage of oil contaminant in a sample.
A second tool that you can use to determine the level of air contamination in oil is one that measures aeration and can be monitored online.
This instrument is based on X-ray transmission, and is able to measure the amount of air in oil as it pumps through a chamber. Resulting data is then reported in various standard conditions, like a 1 bar and 20°C, to get a picture of air levels.
3. Air testing
As well as measuring the levels of air in lubricant samples, a number of trials can be carried out to appraise other factors relating to air contamination. For example, a test using an air-release technique can be carried out to determine how likely an oil is to hold on to entrained air.
In order to carry out this test, compressed air is pumped into a sample of lubricant. The amount of time it takes this air to drop to 0.2 % per volume is subsequently measured. One of the biggest factors that will affect the results of this test is the viscosity of the oil, but other factors, including the oil’s formulation, can also have a bearing on the outcome.
Another method is one that measures the ability of oil to free itself from water. In order to do this, lubricant is mixed with an equal amount of water and placed into a graduated cylinder, where it is left to part. The quicker the oil separates, the better the lubricant.
These are just a few of the methods that can be used to measure air contamination in oil from the likes of Shell and Mobil, and it would serve you well to look into the issue from every angle if you are to keep on top of your oil maintenance.