Properties Of Hydraulic Fluids Research Articles

A REVIEW STUDY IN TROUBLESHOOTING OF HYDRAULIC SYSTEMS IN CEMENT INDUSTRIES

Behind every hydraulic system there exists critical components that influence power transmission. To improve talent you should recognize how these components operate and affect the system i.e. learn the kinds of filter and piping used in hydraulic systems, describe the types and functions of hydraulic seals, and explain the operating principles of different types of pumps, and further learning the types and uses of accumulators, control valves, relief valves, cylinders, and even actuators. In this research study appropriate problem-solving processes are applied, and this helps to comprehend the hydraulic concepts and hydraulic schematic representations. Therefore, it will enhance the knowledge and the capacity of troubleshooting the different hydraulics systems in the cement industry. This will enable the person to stay on top of the industry practices in hydraulics, explore the basics of a hydraulic system by reviewing the types and properties of hydraulic fluids, identifying the symbols used on hydraulic schematic representations, and explaining hydraulic circuit operations based on a schematic design.

Design of a Laboratory Test Equipment for Measuring and Testing Mobile Energy Means with Simulation of Operating Conditions

The presented article deals with the design of equipment for measuring and testing hydrostatic transducers. The presented design of the device is used for measuring and testing hydrostatic transducers in laboratory conditions, especially hydraulic pumps. This shortens the testing time, with a reduction in economic costs for testing the elements of the hydraulic circuit or testing the properties of pumps and hydraulic fluids. By simulating the operating conditions occurring in practice, it is possible to verify and evaluate the parameters of mobile energy means used in hydraulic mechanisms. The designed laboratory equipment is used for measuring and testing hydrostatic transducers and properties of hydraulic fluids. A verification measurement of the flow of the hydrostatic transducer was performed on the proposed laboratory equipment. The output of the measurements is a confirmation of the functionality of the designed equipment. The results of the verification measurement were compared with the data obtained during the simulations in the computer program FluidSIM 5. The output of the measurements is a confirmation of the functionality of the designed equipment. When comparing the results of the verification measurement of the flow on the laboratory equipment with the data given by the manufacturer of the transducer, we recorded a decrease in flow of 5.1% at a speed of 250 rpm in comparison. At 500 rpm we recorded an increase in flow of 2.38% and at 750 rpm there was an increase of 4.15% compared to the data from the manufacturer. The results of the verification measurements were also compared with the simulation in the computer program FluidSIM 5. The flow data obtained by the simulation showed higher values than in the verification measurement. Specifically, at 250 rpm it was an increase of 3.21%, at 500 rpm by 0.39%, and at 750 rpm by 3.14%.

INQUIRY INTO THE EFFECT OF LIQUID CRYSTAL ADDITIVE ON TRIBOLOGICAL PROPERTIES OF HYDRAULIC OILS USED IN TRACK AND CONSTRUCTION MACHINES

The top priority of the modern tribology is to reduce equipment wear. Mechanismsand units of construction and track machines have a lot of friction pairs and the easiest way to reducetheir wear and increase life is to use lubricants. Hydraulic equipment elements are no exception, ashydraulic oils are not only the working fluid of the system, they also lubricate the friction pairs ofhydraulic units. So it is very important that they have an effective lubricity. Pure hydraulic oils havequite low performance properties. To improve them, special substances – additives – are added tolubricants. A large number of relevant compounds have already been studied. A promising trend inthis area is the use of substances that are able to form liquid crystalline phases. It is the substances,which can form cholesterol boundary films on friction surfaces that draw our attention. Based on therelevant works, we selected a liquid crystalline substance with a phenanthrene skeleton of thecholesterol type and conducted a number of experimental studies. This additive was added toindustrial oil. Laboratory studies have confirmed its effectiveness.This research continues to study the effect of liquid crystalline substance with phenanthrene onthe tribological properties of oils used in construction and track machines. As the test oil we choseMobil Hydraulic 10W and John Deere Hy-Gard, working fluids widely used in hydraulic drives inconstruction machines, track machines and agricultural machinery. Both are mineral-based andalready contain additives. Like in our previous studies we used ultrasound to better dissolve theadditive in the oil. The additive dissolved completely. The substance was added to the oil in variousconcentrations. Laboratory studies of tribological properties of hydraulic fluids were performed ona four-ball friction machine in accordance with the standard method described in GOST 9490-75(USSR National standard). The main indicators of lubricity were determined – wear spot diameter,burr index, critical load and welding load. The results of the experiment showed the improvement ofanti-wear and anti-seize properties of the studied hydraulic oils. Within the specified concentrationrange, the greatest anti-wear effect can be observed, which indicates the value of the rationalconcentration of the liquid crystal additive in hydraulic oils. The effect of the additive in the area ofmaximum loads is not significant.

The importance of the electrical properties of hydraulic fluids

PurposeApart from the basic material properties of liquid lubricants, such as, e.g., the viscosity and density of the hydraulic fluid, it is also important to have information regarding the electrical properties of the fluid used. The latter is closely related to the purpose, type, structure, and conditions of use of a hydraulic system, especially the powertrain design and fluid condition monitoring. The insulating capacity of the hydraulic fluid is important in cases where the electric motor of the pump is immersed in the fluid. In other cases, on the basis of changing the electrical conductive properties of the hydraulic fluid, we can refer its condition, and, on this basis, the degree of degradation.Design/methodology/approachThe paper first highlights the importance of knowing the electrical properties of hydraulic fluids and then aims to compare these properties, such as the breakdown voltage of commonly used hydraulic mineral oils and newer ionic fluids suitable for use as hydraulic fluids.FindingsKnowledge of this property is crucial for the design approach of modern hydraulic compact power packs. In the following, the emphasis is on the more advanced use of known electrical quantities, such as electrical conductivity and the dielectric constant of a liquid.Originality/valueBased on the changes in these quantities, we have the possibility of real-time monitoring the hydraulic fluid condition, on the basis of which we judge the degree of fluid degradation and its suitability for further use.

Influence of Properties of Hydraulic Fluid on Pressure Peaks in Axial Piston Pumps’ Chambers

The article concentrates on the research of the pressure peaks in a working chamber of an axial piston pump. The main focus of the article is the influence of fluid properties on the pressure peaks value. Experimental and analytical methods were used to determine the impact of the fluid density, viscosity, compressibility and aeration. The article describes the pressure peak generation process and explains the theoretical basis of this phenomenon. A model of aerated fluid compression and models of leakage were created using CFD analysis and mathematical equations. These partial models were then merged into one consistent model in Matlab Simulink. The final result was verified by comparing the results obtained from the mathematical model with the results of the experiment. After validation, the model was used to present explicitly how each of the mentioned fluid properties affects the pressure peak value. Additionally, the test stand and measurement equipment used in the experiment were presented along with a short description of the laboratory research and sample results.

Impact of undissolved gas on the performance characteristics of hydraulic fluids and characteristic of hydraulic system

Almost in all cases, the hydraulic fluid contains not only the liquid phase of the used oil but also by the gaseous phase, which is often air. Air and oil form a while tanking and pressure drop in particular areas of fluid flow. It can be during dynamic processes due to different rates of gas dissolution and evolution from the fluid. The value of gas compressibility is much bigger than the fluid one, it is necessary to investigate the impact of the gas content of hydraulic fluids on the operation of hydraulic systems. This paper considers analyzing the impact of the gas content of oils on characteristics of hydraulic devices and the properties of hydraulic fluids and the degree of their variation with the amount of undissolved air.

Pre-screening of hydraulic fluids for vane pumps: An alternative to Vickers vane pump tests

The tribological behaviour of hydraulic fluids is mainly evaluated by standardized Vickers vane pump tests, according to ASTM D7043, DIN 51389 or ISO 20763. These tests provide the closest possible representation of actual working conditions, but require many hours of testing and large quantities of hydraulic fluids per experiment, while the frictional behaviour of the tribosystem is not measured. Because of the long testing time, oil quantity and cost, it is impractical to perform multiple tests and this makes the method unsuitable for development purposes. In this work, a new methodology is proposed that allows for a fast and efficient pre-screening and ranking of hydraulic fluids that correlates well with the Vickers vane pump test. To validate the methodology, five different hydraulic fluids are tested and compared to ISO 20763 Vickers vane pump test results. The aim is to achieve similar wear mechanisms and ranking of the anti-wear properties of hydraulic fluids. The future goal is to propose a standardized method that will aid in the development of hydraulic fluids and will complement existing standardized tests.

Tribological properties of hydraulic fluids modified by peat-based additives

The paper presents physicochemical investigations of the structure and properties of a nano-modifier synthesized from peat, the local raw material subjected to pyrolysis in air-free conditions. This nano-modifying additive is a combination of various forms of nanocarbon and polar and non-polar adsorbing materials such as silica (SiO2), calcium carbonate (CaCO3) and carbon (C). Different nanocarbon forms (nanotubes, fullerenes, nanodiamonds, nanofiber, nanodispersed carbon) used in different proportions with micro and macro peat components give multifunctional properties to the synthesized nano-modifier and the ability to positively change tribological properties of hydraulic fluids and oil lubricants. Test results of type TMT-600 show that its different percentage is required to modify tribological properties of the steel tribocouple under different loading conditions. At 0.5 wt.% content of this nano-modifier, stabilization of the friction ratio and an increase of seizure load are observed.

The influence of thermodynamic state of mineral hydraulic oil on flow rate through radial clearance at zero overlap inside the hydraulic components

In control hydraulic components (servo valves, LS regulators, etc.) there is a need for precise mathematical description of fluid flow through radial clearances between the control piston and body of component at zero overlap, small valve opening and small lengths of overlap. Such a mathematical description would allow for a better dynamic analysis and stability analysis of hydraulic systems. The existing formulas in the literature do not take into account the change of the physical properties of the fluid with a change of thermodynamic state of the fluid to determine the flow rate through radial clearances in hydraulic components at zero overlap, a small opening, and a small overlap lengths, which leads to the formation of insufficiently precise mathematical models. In this paper model description of fluid flow through radial clearances at zero overlap is developed, taking into account the changes of physical properties of hydraulic fluid as a function of pressure and temperature. In addition, the experimental verification of the mathematical model is performed.

2D22 Experimental investigation of effective bulk modulus of oil with entrained air bubbles(The 12th International Conference on Motion and Vibration Control)

Although hydraulic systems are compact and have high output power, the demand for further downsized systems with increased output power has been on the rise in recent years. The operating pressures of hydraulic systems have recently been increasing, and condition monitoring of the properties of hydraulic fluid has been one of the most important technical issues. Bulk modulus is a property that indicates the compressibility of a hydraulic fluid. Hydraulic fluids typically become aerated during use, and a certain amount of air is always present in a hydraulic fluid. Aeration strongly influences the bulk modulus of hydraulic fluid because air is significantly more compressible than oil. Entrained air in the form of bubbles reduces the effective bulk modulus. Furthermore, air bubbles entrained in hydraulic fluids cause numerous problems in hydraulic systems. Active bubble elimination devices that use swirl flow capable of eliminating air bubbles from hydraulic fluid have been proposed and developed by the authors. We focus on the relationship between the change in bulk modulus and the elimination of air bubbles from hydraulic fluid. Hydraulic fluid from which bubbles have been eliminated is sampled in a vessel and experimentally pressurized by a servo piston. The volume and pressure change of the sampled oil is measured, and bulk modulus change is calculated to evaluate the bubble elimination. We conclude that the change in bulk modulus of the bubble-eliminated oil influences system performance with respect to positioning, power loss, response time, and stability in hydraulic systems.

Measuring and Modelling Hydraulic Fluid Dynamics at High Pressure—Accurate and Simple Approach

AbstractDynamic properties of hydraulic fluids have to be taken into account in ever increasing fluid power applications. The main reasons are increasing accuracy demands in control and modelling, as well as increasing operating pressure and temperature ranges. Moreover, the already wide spectrum of different hydraulic fluids is also expanding all the time. However, information on dynamic hydraulic fluid behavior is still very difficult to be obtained. On the other hand, existing fluid models tend to be either too inaccurate, or at least highly non-generic for most practical applications.This article introduces simple, yet accurate approaches for measuring and predicting the most important dynamic fluid parameters: bulk modulus, density and speed of sound in fluid. The methods are basically applicable to any standard hydraulic fluid, without any extra system-related constraints, at least at the presented conditions. The studied pressure range reaches 1500 bar, and the temperatures cover a normal operating...

Mechanical testing of hydraulic fluids

The antiwear properties of hydraulic fluids are important because hydraulic pump and motor wear is costly. While international hydraulic fluid performance standards continue to be developed, e. g., the ISO/TC28/SC4 committee's draft ISO DIS 11158 ‘Specifications for mineral oil hydraulic fluids’, the normal hydraulic fluid performance specifications represent minimum requirements. Performance specifications for nonmineral oil hydraulic fluids are also being developed. Typically, both the user and the fluid manufacturer possess insufficient objective information about the antiwear properties of special fluids, e. g., environmentally acceptable hydraulic fluids (EAHF) or fire-resistant hydraulic fluids (FRHF) for use in hydraulic equipment such as axial-piston pumps, vane pumps or radial-piston motors. Manufacturer's specifications must therefore be determined. The required lubrication properties can be determined by either laboratory pump tests or a field trial, often at the customer's expense. The lubrication properties of a hydraulic fluid should ideally be determined under conditions that are equivalent to field practice. This paper will discuss the use of the vane pump test and the FZG gear test to gauge ‘recommended’ hydraulic fluid performance; many non-mineral hydraulic fluids, such as environmentally acceptable hydraulic fluids, fire-resistant fluids or synthetic hydraulic fluids, cannot be used in axial-piston systems based only on results obtained with these tests, and additional testing is always required. Proposals are made for testing of such fluids on a variable-load test rig. These tests are done with axial-piston pumps, or other similar displacement systems, and are intended to determine the industrial suitability of non-mineral hydraulic fluids.

POTENTIAL OF HIGH ERUCIC ACID RAPESEED (BRASSICA NAPUS, VAR. DWARF ESSEX) OIL AS A HYDRAULIC FLUID

Rapeseed oil has been found to be a potentially useful substitute for petroleum-based hydraulic fluid. Thisarticle compares the hydraulic fluid properties of raw rapeseed oil with three commercially available hydraulic fluids:Mobil EAL 224H, PlantoHyd 40, and Hy-TransPlus.<br><br>Experimental results showed that rapeseed oil has hydraulic fluid properties comparable to the three commercialhydraulic fluids. Some of the hydraulic fluid properties, like flash point, viscosity index, and mist spray flammability, werebetter for rapeseed oil.

Evaluation of antiwear properties of hydraulic fluids in pump

Evaluation of antiwear properties of hydraulic fluids in pump