BUBBLE ELIMINATION FOR ENVIRONMENTALLY FRIENDLY DESIGN OF HYDRAULIC SYSTEMS

Abstract

Air entrainment in working fluids has great detrimental effects on function and lifetime of the fluid power components and systems. It is important to eliminate the air bubbles from the working oil to preserve oil quality, system performance, and to avoid possible damage of the components. In view point of environmental compatibility, energy saving, cost saving, and high efficiency, one trend in fluid power systems is for them to be designed in a more compact fashion, requiring less fluid in the reservoir and long lifetime of the working oil. A new device using swirl flow for bubble elimination capable of eliminating bubbles and of decreasing dissolved gases has been developed. In this paper we focus on the technical issue for the air bubbles and aging behavior of the hydraulic oil. In order to investigate the effectiveness of the developed bubble elimination device, changes of oil degradation were experimentally measured on our laboratory test bench under the pump operating conditions during 456 hours of continuous running. Oil specimens are sampled and change of a total acid number and a color is investigated as a function of the working time.