Volume 6, Issue 1 (January 2009)
Effects of Contamination of Biobased Hydraulic Fluids with Mineral Oil
There are many occasions for biobased hydraulic fluids to be contaminated with mineral oil, caused either by incomplete flushing during conversion from mineral oil to bio-oil, or by carelessness during maintenance and refilling. With high contamination levels, problems like foaming, poor air release, or filter clogging have been reported. In experiments at IFAS (Institute for Fluid Power Drives and Controls) of RWTH Aachen University, relevant properties of biobased oils contaminated with different levels of various mineral oils have been analyzed. It was found, that the degree of deterioration correlates not to the amount of mineral oil added, but to the amount of metals introduced through the mineral oil’s additives. Deterioration effects may take several hours or days to develop. The effects are specific for different bio-oil products. As a practical consequence, some changes in quality control, product documentation, and standardization are recommended.