Test rig and comparison of pressure changes at transient phenomena in water- and oil-based power-control hydraulics

The use of tap water instead of the conventional hydraulic fluids in power-control hydraulics is one of possible environmentally friendly changes that we can make. In this paper we show, based on dynamic-transient parameters, both the functionality and the usability of water hydraulics in comparison to the more familiar oil hydraulics. A comparison of the dynamic behavior, oriented to pressures, between the conventional mineral hydraulic oil and the relatively new water hydraulics under the same conditions is described here. The tests were made at different flow rates (11, 22 and 33 lpm), different system pressures (70, 110 and 160 bar) and with different loads (first with a mass of 163 kg in the horizontal and vertical positions and second without this mass). Different dynamic characteristics during the pressure-surge effect of water and oil hydraulics were observed. The pressure increases were between 10 and 30 % higher in the water hydraulics than in the oil hydraulics. The frequencies of the pressure oscillations were up to 20 % lower in the water hydraulics than in the oil hydraulics.