Abstract
Environmental protection regulations are becoming increasingly strict. By using water instead of a hydraulic mineral oil in power-control hydraulic systems we can make a very positive step in complying with these regulations. In this paper we present some preliminary results on twin-type hydraulic experiments, employing equal parts containing water and oil. Our initial findings suggest the need for modifications to the test rig, and a comparison of the behaviour between two similar hydraulic test rigs is shown. The main parameters measured during the investigation were the pressures, the spool displacements and the responses of the piston in the double-acting hydraulic cylinder. However, transient phenomena in the water and oil hydraulic test rig were also analysed and compared. Experiments were performed on systems with and without an applied load. The results reveal very different behaviours for the oil and the water hydraulics.
