Monitoring the condition of hydraulic oils

The contamination of hydraulic oils and hydrocarbon fuels as a result of moisture and particles is a huge problem in many industrial sectors.

Regular checks are crucial in preventing contamination, but many traditional tests, such as visual inspection, are no longer up to scratch.

The simplest check used is the Clear and Bright (C&B) test for hydrocarbon fuels - also known as the White Bucket test. This technique essentially involves an operator taking a sample of the fuel to be tested and observing it. If they are able to see any solid particles, or the fuel is hazy when held up to the light, the fuel fails the test. Although this test gives an indication of contamination, it suffers from a number of limitations.

The test is highly subjective; the eyesight of the person looking at the sample, the light conditions at the time and the type of container in which the sample is held can all have an impact on the results. This is because the human eye is only capable of seeing objects of 30-40µ in size or larger; under normal circumstances, these relatively large particles will drop out of suspension.