Some rheological properties of new and used mineral lubricant and biolubricant for tractors

J. Csillag¹, A. Petrović¹,*, V. Vozárová¹, J. Kosiba2 and R. Majdan²

¹Slovak University of Agriculture in Nitra, Faculty of Engineering, Department of Physics, Trieda Andreja Hlinku 2, SK949 01 Nitra, Slovakia
²Slovak University of Agriculture in Nitra, Faculty of Engineering, Department of Transport and Handling, Trieda Andreja Hlinku 2, SK949 01 Nitra, Slovakia
*Correspondence: ana.petrovic@uniag.sk

Abstract:

It is important to know physical characteristics of lubricating oils to ensure the highest reliability for operation of device. The use of ecological lubricants depends on their characteristics; the most important are density and viscosity, protection against wear and tear, corrosion resistance etc. The objective of this work was to find changes of the rheological properties of the synthetic oil and bio lubricant. We compared two different oils in our measurements. One sample was synthetic oil and the other was mineral oil (bio lubricant). Both oils are universal oils for tractors. Further, comparison of new and used sample after million cycles was performed. The density and the dynamic viscosity show strong exponentially decreasing dependence. With the increasing temperature, values of the both properties, decreased. It can be also observed that used samples have lower viscosity and density. The results presented in this article can be important when putting ecological lubricants into operation.

Key words:

Diagnostics of hydraulic fluids used in aviation

M. Obergruber¹, V. Hönig¹*, P. Procházka² and J. Táborský¹

¹Czech University of Life Sciences Prague, Faculty of Agrobiology, Food and Natural Resources, Department of Chemistry, Kamýcká 129, CZ16521 Prague 6, Czech Republic
²Czech University of Life Sciences Prague, Faculty of Economics and Management, Department of Economics, Kamýcká 129, CZ16521 Prague 6, Czech Republic
*Correspondence: honig@af.czu.cz

Abstract:

Diagnostics is a maintenance industry that monitors performance, parameters, and follow–up. Diagnosing hydraulic fluids means comparing the parameters of the used hydraulic fluid sample to the parameters of the clean fluid. It is also essential to monitor the limit values either by the aircraft manufacturer or by the manufacturer of the hydraulic fluid. This means that the manufacturer recommends the limitations of the liquid parameters. The measurements of the fluid samples give an overview of the liquid quality. Most businesses focus on so–called proactive maintenance. The main senses and objectives of proactive maintenance are: lubricant sample analysis, lubricant status, machine status, next step recommendation, database saving and trend analysis. This article focuses on the quality of hydraulic fluid focused in aviation. The aim of the article was to determine the properties of the hydraulic fluid used in the A320 aircraft family, determine the interval of its exchange. Monitoring the state of the hydraulic fluid could contribute to the timely detection of the problem, thus avoiding a failure of the device or the system as a whole. The tracking proposal is an integral part of this article.

Key words:

cleanliness code, control interval, hydraulic fluid, kinematic viscosity, particle analysis