Development of components and systems for tap water power-control hydraulics

Project duration

2007 - 2008

Project Category


Contact Information

prof. dr. Mitjan Kalin


TAJFUN Planina d.o.o. (Slovenia)

From the environmental point of view the use of oil power-control hydraulics in machines and production lines is very problematic, especially for the machines working in the environmental areas. From the nature conservation and furthermore from the fire safety point of view only the water is harmless. Tap water as hydraulic fluid is the object of our investigations in the proposed research project.

According to statistical data 85 % of all kinds of hydraulic fluids is still represented by hydraulic mineral oil. As it is well known, hydraulic mineral oils are very harmful to the environment, especially in the areas where the underground water is used as drinking water. A reliable prevention of random outflow of fluid from the hydraulic system does not exist.

In the past years in the Laboratory for Power-Control Hydraulics (LPCH) and also within the scope of the complete Laboratory for Tribology and Interface Nanotechnology (L-TINT) we have investigated the fluid flow through the circular gaps in the field of oil power-control hydraulics. The testings were carried out and the mathematical model for these flows was derived too. A lot of comparative analyses is still to be done, especially those concerning and correlating the mathematical model and the results of the measurements.

In the scope of the work on this research project first the relevant literature concerning this project is to be reviewed. We intend to investigate how tap water under pressure influences on the individual components, especially certain kinds of valves and hydraulic cylinders. The fluid flow and accompanying pressure will be created using axial piston pump. Inside the hydraulic components the critical points and critical boundary parameters for their function need to be foreseen. For this reason some simple testings will be carried out. On the basis of these testings the laboratory testing rig will be designed and constructional design of specimens will be made.

One of the basis of our research is the comparison between water and mineral oil as two hydraulic fluids. Therefore the testing rig will be designed as a double rig, i.e. two equal testing rigs. The tests will be carried out in parallel. In the first testing rig tap water will be used as hydraulic fluid and in the second the mineral hydraulic oil. Specimens in both testing rigs will be equal as well as the testing parameters; flow, pressure, working and geometrical parameters. In the long-term tests wear will be monitored within the components of water-driven hydraulic system (PKH), the parameters to improve wear resistance will be determined and compared to wear of oil-driven PKH.