Research regarding the usabilities of ionic liquids within hydraulic systems

Vsaka vrsta hidravlične tekočine ima svoje prednosti za določen primer uporabe. Voda, kot prva in tudi v zadnjih letih ponovno aktualna hidravlična tekočina je negorljiva, praktično nestisljiva, neškodljiva za zdravje človeka ter okolje, cenena in razpoložljiva skoraj povsod. Mineralno olje je možno uporabiti skoraj povsod in v raznovrstni opremi. Težko vnetljive hidravlične tekočine zaradi večje varnosti pred požarom uporabljamo predvsem v metalurških obratih in premogovnikih, biološko hitreje razgradljive hidravlične tekočine pa zaradi manjše nevarnosti za okolje predvsem v mobilni hidravliki. Poleg prednosti pa ima vsaka vrsta hidravlične tekočine tudi slabosti, tako da je pri izbiri najbolj primerne vedno potreben nek kompromis. Idealne rešitve ni, radi pa bi se ji vsaj približali. Cilj doktorske disertacije je bil, da v praktično neomejenem številu različnih ionskih tekočin, skušamo poiskati nekaj primernih za uporabo v hidravličnih sistemih in na ta način predlagati bodočo alternativo današnjim, običajno uporabljanim hidravličnim tekočinam. V ta namen so obravnavane osnovne lastnosti ionskih tekočin in njihove prednosti. Primernost smo ugotavljali tako na osnovi meritev fizikalno kemijskih lastnosti, kot tudi na osnovi praktičnih testov, aktualnih za hidravlične tekočine. V disertaciji so uporabljene laboratorijske in praktične testne metode tudi podrobneje opisane. Veliko pozornosti je posvečeno sposobnosti korozijske zaščite, saj večina testiranih vzorcev ni nudila zadostne zaščite pred korozijo. Prav tako je podrobneje obravnavana stisljivost, saj ima neposreden vpliv na porabo energije in odzivnost hidravličnih sistemov. Pri iskanju ionske tekočine, ki bi bila primerna za uporabo v hidravličnih sistemih se je izkazalo, da kljub nekaterim boljšim rezultatom v primerjavi s konvencionalnimi hidravličnimi tekočinami, (za sedaj) ni veliko takih, ki bi vse potrebne lastnosti imele vsaj na trenutnem nivoju konvencionalnih hidravličnih tekočin.Each type of hydraulic fluid has its advantages in regard to its specific use. Water, as the first and over past years also a promising hydraulic fluid, is non-flammable, virtually incompressible, harmless to human health and the environment, inexpensive, and available almost everywhere. Mineral oil can be used almost anywhere and in miscellaneous equipment. Fire-resistant hydraulic fluids are mainly used in metallurgical plants and coal mines because of greater fire safety, whereas bio-degradable hydraulic fluids are commonly used in mobile hydraulics due to environmental protection. However, besides its advantages, each type of hydraulic fluid also has its disadvantages. Therefore, selecting the more appropriate always requires compromise. There are no ideal solutions, but we would like to attain them as closely as possible. The aim of this doctoral thesis was to discover, from amongst a virtually unlimited number of different ionic liquids, an ionic liquid suitable for use in hydraulic equipment and to suggest a future alternative to today’s commonly used hydraulic fluids. The basic properties of ionic liquids and their benefits are considered for that reason. Their suitability were determined based on measurements of physical and chemical properties as well as on practical test for hydraulic fluids. Laboratory and practical test methods are also described in detail. Great attention was paid to corrosion protection performance, as most of the samples tested offered insufficient protection against corrosion. Compressibility is also discussed in detail, considering it has a direct impact on energy consumption and the response of the hydraulic system. Research regarding the usability of ionic liquids within hydraulic systems revealed, that despite some better results for ionic liquids, few of them had all the necessary features of conventional hydraulic fluids required by today’s hydraulic systems