Rapidly biodegradable hydraulic fluids on the basis of rapeseed oil

R. Šraj, J. Vižintin, M. Svoljšak, M. Feldin

Lubrication Eengineering 56 (2000) 34–39.


Hydraulic fluids based on mineral oils have 83% of the market today. The vegetable oils have only 2%, but the prognosis for the year 2000 foresees that hydraulic fluids based on vegetable oils could reach about 8% of market share. On the other hand some industrialized and small countries, like Slovenia, have considered legislative measures to help prevent environmental pollution and to protect natural resources. Rapeseed oils can offer significant environmental advantages with respect to resource renewability, biodegradability and toxicity when compared to mineral oils. The laboratory test results for one vegetable and one mineral base hydraulic fluid are described in this paper. The results of their physical, chemical and mechanical properties have been obtained by the standard tests for hydraulic fluids. Through simulated real working parameters modeling a dredge on a model laboratory hydraulic system, the behaviour of rapeseed and mineral hydraulic fluids have been studied. After the laboratory tests, the rapeseed base fluids were tested on the hydraulic system on the dredger in praxis. During these tests operating temperature, fluid pressure, acid number (TAN), viscosity, number of particles and water content were simultaneously analysed. The contact surface roughness of hydraulic elements before and after the tests were measured. The ageing of the test oils was analysed using Fourier transform infrared (FTIR) spectroscopy.

Keywords: lubricants, rapeseed oils, vegetable oils, hydraulic fluids, lubricant properties, lubricant stability, biodegradability, toxicity, field testing

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