Hydraulic Liquids Research Articles

Ionic Hydraulic Fluids and Seal-Material Compatibility

Manufacturers of hydraulic fluids invest a lot of effort and resources in improving their physico-chemical properties, with the goal of getting as close as possible to the properties of an ideal hydraulic fluid. It should be non- flammable, environmentally friendly, sustainable and should have excellent physical and chemical properties. After decades of development in the field of ionic liquids and the search for an ionic liquid suitable for use in hydraulic systems, ionic hydraulic liquids are now already in industrial use, especially on devices that operate in harsh and risky operating conditions. Since ionic hydraulic fluids are a completely new type of hydraulic fluid, one of the issues is their compatibility with the materials present in the hydraulic components, including all the seals. This paper refers to the process of testing the compatibility of hydraulic seal materials with different types of ionic hydraulic fluids according to the standardized percentages and recommendations, with emphasis on changes in the swell, shrinkage and hardness of the seals. The presented results are a useful guide for selecting suitable seal materials in case of using high-tech ionic hydraulic fluids.

Comparison of Chemical and Enzymatic Methods for the Transesterification of Waste Fish Oil Fatty Ethyl Esters with Different Alcohols.

Fatty acid esters of 2-ethyl-1-hexanol (EH), 2-hexyl-1-decanol (HD), and isopropanol have been obtained from a mixture of ethyl esters obtained as a fish oil byproduct. Homogeneous base catalysis with alkaline hydroxides and alkoxides has been compared with the use of two commercially available immobilized lipases. The enzymatic methodology is more efficient in the case of the largest alcohol (HD) mainly because of the high stability of the immobilized enzymes upon recovery and reuse. In contrast, the use of a base as a catalyst is highly favorable in the case of isopropanol because of the rather poor activity of the lipases and the low price of the bases. With EH, the activity of lipases is good but the recoverability is not as efficient; hence, basic catalysts are again the most attractive alternative. The mixtures of esters obtained may be useful as hydraulic liquids given their viscosity values.

Experimental Hydraulic Device for the Testing of Hydraulic Pumps and Liquids

Experimental Hydraulic Device for the Testing of Hydraulic Pumps and Liquids

Modeling of Cavitation-Induced Air Release Phenomena in Micro-Orifice Flows

Impurities like air bubbles in hydraulic liquids can significantly affect the performance and reliability of hydraulic systems. The aim of this study was to develop a model suited for hydraulic system simulation to determine the rate of degassing of dissolved air in a micro-orifice flow at cavitating conditions. An existing model for the flow through a micro-orifice was extended to account for the generation of vapor which is suggested to play the key-role for the degassing mechanism. In comparison with measurements, the results of the modeling approach imply that diffusive mass transfer of dissolved air into generated vapor cavities is the dominating mechanism for the observed air release phenomena.

A mathematical model of the inline CMOS matrix sensor for investigation of particles in hydraulic liquids

One of the most effective ways to diagnose the state of hydraulic system is an investigation of the particles in their liquids. The sizes of such particles range from 2 to 200 gm and their concentration and shape reveal important information about the current state of equipment and the necessity of maintenance. In-line automatic particle counters (APC), which are built into hydraulic system, are widely used for determination of particle size and concentration. These counters are based on a single photodiode and a light emitting diode (LED); however, samples of liquid are needed for analysis using microscope or industrial video camera in order to get information about particle shapes. The act of obtaining the sample leads to contamination by other particles from the air or from the sample tube, meaning that the results are usually corrupted. Using the CMOS or CCD matrix sensor without any lens for inline APC is the solution proposed by authors. In this case the matrix sensors are put into the liquid channel of the hydraulic system and illuminated by LED. This system could be stable in arduous conditions like high pressure and the vibration of the hydraulic system; however, the image or signal from that matrix sensor needs to be processed differently in comparison with the signal from microscope or industrial video camera because of relatively short distance between LED and sensor. This paper introduces mathematical model of a sensor with CMOS and LED, which can be built into hydraulic system. It is also provided a computational algorithm and results, which can be useful for calculation of particle sizes and shapes using the signal from the CMOS matrix sensor.

QUALITY CONTROL OF HYDRAULIC LIQUID OF «HYDRONIKOIL» FH-51 AT THE PROTRACTED USE: PROBLEMS AND TASKS

In the directive of ІCАО Doc 9735 tasks are set forth on creation in every state of corresponding national organs for control of activity on providing of safety of flights and connections on these questions with the committees of ICАО. The operating national checking of quality control system of hydraulic liquids is regulated by Instruction that is ratified in 2006 and worked out with the use of out-of-date normatively-legal acts. Until now additions, that would reflect the tasks set forth in Doc 9735 in the direction of quality control of hydraulic liquids at protracted, are not brought in Instruction. It is experimentally set that at the protracted use of hydraulic liquid of «Hydronikoil» FH-51 compounds that cause to reduction of her oxidizing stability appear. The existent quality control system is not able to forecast the change of operating properties of hydraulic liquid at the protracted use. Therefore is not possible to foresee development of refuses and disrepairs of aggregates of the hydraulic system of air ship, that creates the serious threat of safety of flights. Taking into account aforesaid, it is necessary to harmonize the operating quality control system of hydraulic liquids in accordance with the tasks of ICАО; to work out control system quality of hydraulic liquids at the protracted use; to create the system of providing of safety of flights in the part regarding to the protracted use of hydraulic liquids; to harmonize these systems with modern international requirements, taking into account national features.

Leakage monitoring using percolation sensors for revealing structural damage in engineering structures

There is a continuous need for the monitoring of engineering structures, especially when scheduled inspections are difficult to perform or if they are too expensive. The present paper gives some results on the performance of sensors on the basis of percolation thresholds that are able to detect leakage of diverse harmful liquids, such as water, hydraulic liquids, kerosene and jet engine oils. The focus here lies on sensor systems that give semi-quantitative, fuse-like information on the presence of harmful liquids, which indirectly gives evidence on the presence of structural damage. The common underlying principle is the interruption of percolation conductivity when the respective sensing material is exposed to harmful liquids; that is, the electrical conductivity is essentially lost by sorption and swelling of a dedicated matrix material. The temperature dependence and response times give valuable information on the usability of the sensor in the respective environments. The sensor can be manufactured as a cord sensor or as self-adhesive patches where the functional layer is deposited by screen printing. Copyright © 2013 John Wiley & Sons, Ltd.

The improvement of functional features of antifriction polymer composites for sliding friction units

Present situation in the field of friction materials science is discussed and new antifriction materials are described. Special attention is paid to polymer carbon plastics UGET and FUT and their modification for the friction units with water lubricant. The advantages of the developed carbon plastics and their modified types consist in high mechanical strength, impact resistance, reliable work under dynamic stresses and high hydrostatic pressures with almost all types of lubrication (water, acids, alkali, oils, hydraulic liquids, and others) and counter-bodies made of different materials (steel, bronze, titanium alloys, ceramics, etc.).

HYDRAULIC SYSTEM MAINTENANCE

Any problem in a hydraulic system in any hydraulic equipment, while working, may decrease the investment to outweigh the cost of maintenance or reconstruction. The hydraulic cylinder is a main component in the hydraulic systems. In most cases of forced stop, the equipment malfunctions in the hydraulic cylinder and its components. Therefore this study aims to repair the performance of hydraulic cylinder after corrosion and determine the best ways for the reconstruction and maintenance of hydraulic cylinder. Also, to study of the electroplating of internal surface of hydraulic cylinder, which is supposed to raise the economic life of the cylinders and consequently the economic life of machine. The studied factors were:(a) treating the surface of cylinder (before treatment, turning, polishing, chromium electroplating) and measuring the force needed to move the piston in the presence of three kinds of oils ( ISO VG numbers are VG32 ,VG22 and VG10 ) as hydraulic liquids and (b) the effect of piston on the cylinder performance (without pressure ring, with one pressure ring and with two pressure rings) after each treatment on the cylinder surface, to evaluate the effect of the previous factors on the cylinder performance (measured by the specific force needed to move piston).. The final data indicated that electroplating of the inner surface of the hydraulic cylinder resulted in improving the performance of the hydraulic cylinder.

Potential applications of poly(vinyl alcohol)‐congo red aqueous solutions and hydrogels as liquids for hydraulic fracturing

AbstractThe authors report on the viscoelastic characterization of guar hydrogels obtained through complexation reactions with borax ions. These gels are compared with hydrogels obtained from poly(vinyl alcohol) of different degree of hydrolysis through complexation reactions with congo red. The effect of the degree of hydrolysis and both, the concentration of PVA and the concentration of congo red, on the viscoelastic properties of the hydrogels is analyzed. The potential use of the PVA‐based hydrogels as hydraulic fracturing liquids is discussed in relation to the commonly used fracturing liquid based on the guar–borax system. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

Investigation of chemical transformations in the hydrocarbon composition of the working fluid "hidronikoyl» fh-51

The results of structurally-group composition research of standards of commodity and after 3600 hours flight of aviation hydraulic liquid of «Гидроникойл» FH-51 are presented. Given liquid was investigated by the methods of distillation and liquid chromatography. Obtained results demonstrate that after thermal-oxidative degradation of carbohydrates it composition changes. And as a result the quality and running ability of considered working liquid decrease. Today airline enterprises quality control system does not check such chemical transformations in hydraulic liquids composition. Thus, it is confirmed, that present quality control system of hydraulic liquids is not scientifically valid and it does not provide modern high demands to saving of a working liquid quality at it exploitation in airplane hydraulic system .Therefore the task of improvement of the existent quality control system of hydraulic liquids is actual.

Study of modern state of quality control hydraulic liquids

In the work present of investigation results of the state control quality system of hydraulic liquids in the contemporary modem conditions of the consumption and storage. To present the results of investigation of change hydraulic liquids quality in the exploitation aviations technical. Propose the directions the perfection of the control quality liquids for hydraulic system aircraft.

Membrane permeation based sensing for dissolved water in organic micro-aqueous media

The water content of solutions is important for fuels, lubricants, hydraulic liquids, oils and fats, and enzymatic catalysis in organic liquids. Rapid and accurate on-line water detection is needed for research and for the technical realization including process optimization of enzymatic catalysis in organic liquids. This paper reports on the development of sensors that rely on the selective pervaporation of water from micro-aqueous organic liquids to the vapor phase through a polymeric membrane. This sensing principle employs the transport of water exploiting both diffusion and sorption. The water content of liquid n-hexane and kerosene is sensed from saturation down to concentrations in the low ppm range. The isothermal sensor response is shown to be largely linear with dissolved water concentration.

Sensitivity of Anaerobic Rumen Fungi to Pentachlorphenol and Pentachlorbiphenyl

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Improvement of the tribological properties of hydraulic liquids

Improvement of the tribological properties of hydraulic liquids