Conventionally, carboxylic acid salts are widely applied as antiwear additives for water-glycol (W/G) hydraulic fluids. For this study, a Mini Traction Machine (MTM) was employed to evaluate the ...friction properties of four carboxylates in W/G fluid. The results indicate that undecylenate salt (CN-3) exhibits the best antifriction capability and the friction coefficient nearly remains stable when its concentration increases from 3 wt% to 6 wt%. However, ball-on-disk tribology tests show that CN-3 as a single lubricant additive causes poor lubrication under severe conditions like a high load of 125 N. Fortunately, the combination of CN-3 and a water-soluble heterocyclic compound (COMB) led to outstanding antiwear and friction-reducing properties. A possible reason is the formation of a more stable tribofilm containing FeS
2
and carbon structures, according to x-ray photoelectron spectroscopy (XPS) analysis of the worn surfaces. Furthermore, a vane pump test was conducted to confirm the results of the simulating tests. The W/G hydraulic fluid formulation based on COMB as the antiwear package performs well in the pump test, giving rise to only slight pump wear loss. The results of the pump test and the simulating test are consistent with each other. Meanwhile, the W/G hydraulic fluid possesses excellent other physicochemical properties and meets the specification of ISO 12922.
Modern robots lack the multifunctional interconnected systems found in living organisms and are consequently unable to reproduce their efficiency and autonomy. Energy-storage systems are among the ...most crucial limitations to robot autonomy, but their size, weight, material and design constraints can be re-examined in the context of multifunctional, bio-inspired applications. Here we present a synthetic energy-dense circulatory system embedded in an untethered, aquatic soft robot. Modelled after redox flow batteries, this synthetic vascular system combines the functions of hydraulic force transmission, actuation and energy storage into a single integrated design that geometrically increases the energy density of the robot to enable operation for long durations (up to 36 hours). The fabrication techniques and flexible materials used in its construction enable the vascular system to be created with complex form factors that continuously deform with the robot's movement. This use of electrochemical energy storage in hydraulic fluids could facilitate increased energy density, autonomy, efficiency and multifunctionality in future robot designs.
Bench Test of a Hydraulic Biofluid Based on Refined Pomace Oil Fanigliulo, Roberto; Bondioli, Paolo; Fornaciari, Laura ...
European journal of lipid science and technology,
December 2021, 2021-12-00, 20211201, Volume:
123, Issue:
12
Journal Article
Peer reviewed
This paper aims at investigating the possibility of replacing conventional hydraulic fluids with refined olive pomace oil added with a common food grade antioxidant, as hydraulic fluid for ...agricultural machinery. The fluid efficiency test is carried out using an experimental test rig based on a hydraulic system designed to apply severe work cycles (pressure values up to 40 MPa; temperatures up to 100 °C) to small oil volumes with the aim of strongly accelerating the ageing of the tested fluid. The fluid, added with 2 g kg−1 of antioxidant, apparently does not undergo any changes in chemical‐physical properties and maintains stable the technical performance of the test equipment during 530 h work cycle. This research has four different goals: i) to contribute to the circular economy, by using olive oil byproducts in agricultural environment; ii) to contribute to the reduction of environmental contamination by substituting petroleum products with natural biodegradable ones; iii) to contribute to avoid the presence of mineral products (such as saturated hydrocarbons, which could accumulate in human organs, and aromatic hydrocarbons, which are potentially genotoxic), as a residue in food products and in vegetable oils. iv) to identify alternative market possibilities for such a by‐product.
Practical applications: The results of the study seem to indicate the possibility of using the olive pomace oil as hydraulic fluid, for example, in agricultural machinery, opening new market perspectives which would increase its added value.
The possibility to replace conventional hydraulic fluids with refined olive pomace oil added with an antioxidant, for agricultural applications, is evaluated in a fluid efficiency test by means of a test rig designed to apply severe work cycles (pressure up to 40 MPa; temperature up to 100 °C) with the aim of strongly accelerating the ageing of the tested fluid.
The presence of microscopic particles in suspension in industrial fluids is often an early warning of latent or imminent failures in the equipment or processes where they are being used. This ...manuscript describes work undertaken to integrate different photonic principles with a micro- mechanical fluidic structure and an embedded processor to develop a fully autonomous wear debris sensor for in-line monitoring of industrial fluids. Lens-less microscopy, stroboscopic illumination, a CMOS imager and embedded machine vision technologies have been merged to develop a sensor solution that is able to detect and quantify the number and size of micrometric particles suspended in a continuous flow of a fluid. A laboratory test-bench has been arranged for setting up the configuration of the optical components targeting a static oil sample and then a sensor prototype has been developed for migrating the measurement principles to real conditions in terms of operating pressure and flow rate of the oil. Imaging performance is quantified using micro calibrated samples, as well as by measuring real used lubricated oils. Sampling a large fluid volume with a decent 2D spatial resolution, this photonic micro sensor offers a powerful tool at very low cost and compacted size for in-line wear debris monitoring.
Synthetic and vegetable oil based esters offer the best choice in formulating environment friendly lubricants. In the present review an attempt has been made to highlight some recent developments in ...the area of biodegradable synthetic ester base stocks for formulation of new generation lubricants including the efforts made so far at the author's laboratory in this direction. The developed products find applications in automotive transmission fluids, metal working fluids, cold rolling oils, fire resistant hydraulic fluids, industrial gear oils, neat cutting oils and automotive gear lubricants either alone or in formulations.
Hydraulic fluids are commonly used for mechanical power transfer and lubrication. New hydraulic fluids are commonly compared to benchmark products with respect to qualities which include energy ...transfer efficiency and corrosion resistance. In this case, an energy transfer efficiency performance comparison was conducted on an injection molding system when it used a conventional fluid and when it used an alternative synthetic hydraulic fluid. Data analysis demonstrated a potential 16.7% overall energy consumption reduction when the conventional fluid was replaced by the alternative synthetic hydraulic fluid.
The article dealt with the assessment of the quality of hydraulic oil and determination of the mode of wear of the friction surfaces of Baljer & Zembrod manipulating lines through the information ...traces in the oils by applying tribotechnical diagnostics. We presented the assessment of the level of degradation of the oils. In addition, we presented the mode of wear of the friction surfaces washed in oil through evaluation of the qualitative and quantitative characteristics of the particles found in the oil. In detail, we focused on the application of suitable multivariate statistical methods on the data matrix. The article also presents predictive models that can sort oils into groups based on the assessment of quality of the oil and the state of the friction couples. The models can be used in research and in solving practical tasks in tribotechnical diagnostics of hydraulic fluids in woodworking equipment. Our results showed that the manipulation lines were greatly thermically stressed due to inadequate oil and machine maintenance. By correlative integration of all methods used, we could determine the real mode of the wear of the tribologic nodes of the machine. The experiment enabled the early detection of an undesirable process in the tribological node and implementation of corrective measures before the machine would break down.
Green biolubricant base stock based on crude palm oil fatty acids (CPOFAs) was produced through acid catalyst esterification of palm oil fatty acids with neopentyl glycol (NPG). The response surface ...methodology (RSM) of D-optimal design was employed to optimize the esterification process. The resultant polyol ester, crude palm oil fatty acids-NPG diester (CPOFAs-NPGDE) was evaluated its lubrication properties. The optimal condition for the esterification process was obtained at CPOFAs:NPG molar ratio of 2.26:1, 1.12% H2SO4 catalyst, reaction temperature of 138 °C for 4.79 h reaction time, respectively. The optimal CPOFAs-NPGDE produced was 87.6% yield with 100% diester selectivity. The resultant ester showed good lubrication properties with oxidative stability temperature at 184 °C, pour point at 10 °C, flash point at 235 °C and viscosity index of 190. Tribological tests showed that COFAs-NPGDE has shown low coefficient friction of hydrodynamic regime of 0.20 at 40 °C and 0.19 at 100 °C and comparable with some commercial lubricants. Rheological tests show that CPOFAs-NPGDE can be classified as a Newtonian fluid with good lubrication properties within ISO VG 46 lubricant grade. This make it plausible to be used for green industrial lubrication applications such as hydraulic oil, compressor and turbine fluids.
Application Areas of Ionic Hydraulic Fluids Lovrec, Darko; Kalb, Roland; Tič, Vito
Chemical engineering & technology,
January 2023, 2023-01-00, 20230101, Volume:
46, Issue:
1
Journal Article
Peer reviewed
Open access
Ionic liquids, as high‐tech technical fluids, have been in practical application in various fields of technology for several years. The search for ionic liquids suitable for use within hydraulic ...systems, as another new very important field of technology, has taken more than a decade. The development included the identification of material properties important for usage as a hydraulic fluid, an extensive preselection process and laboratory testing of suitable ionic liquids, as well as long‐term testing using real hydraulic components under real operating conditions. Based on the findings, potential areas of industrial application of ionic liquids as hydraulic fluids are presented, which arise from their extraordinary physicochemical properties.
Ionic liquids as high‐tech technical fluids have also made their way into the field of hydraulic drives. With excellent lubricating properties, a wide temperature range, low pour point and vapor pressure, as well as nonflammability and environmental suitability, problems with only one type of fluid, namely, an ionic hydraulic fluid, instead of using different hydraulic fluid types can be solved.
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