Zdeněk Aleš

POSSIBILITY OF HYDRAULIC FLUIDS WITH A LOW ENVIRONMENTAL IMPACT APPLICATION IN AGRICULTURE AND TRANSPORT MACHINERY

Agricultural and transport equipment is ideally suited to use hydraulic oils. After engine oils, hydraulic fluids are the second most important group of lubricants. More than 85 % of these materials are currently mineral oil-based. In view of their high ecotoxicity and low biodegradability, mineral oil-based lubricants constitute a considerable threat to the environment. In contrast, most hydraulic fluids based on plant oils have a low environmental impact and are completely biodegradable. Moreover, lubricants based on plant oils display excellent tribological properties and generally have very high viscosity indices and flash points. For this reason, therefore, particularly soybean, sunflower and rapeseed seem to possess the relevant properties as a potential hydraulic fluid. There are several tribotechnical methods how to assess the current technical state of used lubricants (viscosity, water content, flash point, acidity). One of the modern methods how to detect wear particles is LaserNet Fines, which is a suitable technique for machine condition monitoring. The ageing of test oils is analysed by the Fourier transform infrared spectroscopy (FT-IR); for determining anti-wear properties of hydraulic oils, the standard STN EN ISO 20623:2004 indicates 1 hour under an applied load of 150 N. The objective of the paper is to show the description and examples of modern tribotechnical methods used for determination of the technical state of used biolubricants utilized in agriculture and transport machinery.

Applying of Automatic Laser Particle Counter as Technique to Morphology Assessment and Distribution of Wear Particles during Lifetime of Transmission Oils

Vast part of environment pollution is caused by the lubricants. Lubricants are mostly of mineral origin. They are toxic and not easily biodegradable. Transition to biodegradable oils involves several technical issues. During the operation of machines and equipment wear occurs due to formation of particles that pollute the lubricant fillings. Cleanliness of the oils in lubrication systems is an important prerequisite for maintaining the operating conditions of machines and equipment.The aim of this article is to evaluate distribution of wear particles of tested transmission oil samples via automatic laser particle counter and classifier LaserNet Fines-C which is highly accurate and a fully automated tribotechnical diagnostics device.

Morphology Analysis of Friction Particles Generated in Tractor Transmission Oils

Abstract The aim of the study was the examination of the morphological and compositional attributes of wear particles of tested universal tractor transmission oil (UTTO) samples by means of automatic particle counter and classifier LaserNetFinesTM-C, which is an ideal tool to establish the dynamic equilibrium concentration and hence to set the alarm limits for any type of machine. Such limits can be based on wear type and particle size ranges. The samples of two UTTO (mineral oil and biodegradable fully synthetic oil) were taken from the rear gearboxes of the wheel tractor during a long-term experiment. The measurement results showed that there was faster increase in the particle wear of mineral oil in comparison to biodegradable transmission oil. Considering the increase in the percentage of particles over 20 μm, the biodegradable oil seems to be more favourable for usage. Regardless of this, it can be concluded that the biodegradable oil is equivalent to petroleum-based oils.

Notice of Retraction Degradation process influencing safety of constructional adhesive bonds

Undesirable degradation processes affect the constructional adhesive bonds, which gradually deteriorate the adhesive bond parameters. This fact manifests the topicality of given problems with simultaneous noting of the increasing trend of using the adhesive bonding technology. The presumption or prospective elimination of threatened marginal states depends on the understanding of the process causing this state. The aim of the experiment is to study and experimentally verify the degradation processes that influence running in the adhesive bonds. Furthermore, based on statistical methods ANOVA, an influence agreement of single liquid contaminants types based on industrial and mineral fertilizers needs to be determined.