Lubricants, industrial oils and related products (class L) - Family H (Hydraulic systems) - Specifications for hydraulic fluids in categories HFAE, HFAS, HFB, HFC, HFDR and HFDU

2020 ◽  
2014 ◽  
Vol 60 (Special Issue) ◽  
pp. S37-S43 ◽  
Author(s):  
I. Janoško ◽  
T. Polonec ◽  
S. Lindák

In environmental terms, hydraulic fluids used in the hydraulic system of municipal vehicles represent problems related to a potential leakage from the system into the environment and the subsequent contamination of groundwater and soil. More environment-friendly way is to use green hydraulic fluids that are biodegradable in accidents. This paper aims to investigate the possibilities of biodegradable oil application and its adaptation in the hydraulic systems of municipal vehicles by monitoring the impact of the bio-oil Mobil EAL 46 ESSO on the performance parameters as flow, efficiency, durability, etc. Hydraulic pump revolutions were measured using a non-contact sensor based on the principle of magnetic induction change. Method of tightness monitoring was used to achieve results for functionality and wear of the hydraulic system. During 600 h of the test period no significant deterioration of performance parameters was detected. Results are useful for companies involved in waste collection.


2020 ◽  
Vol 10 (24) ◽  
pp. 9086
Author(s):  
Artur Olszak ◽  
Karol Osowski ◽  
Ireneusz Musiałek ◽  
Elżbieta Rogoś ◽  
Andrzej Kęsy ◽  
...  

This paper presents the results of physicochemical and tribological tests of vegetable oils obtained by the supercritical fluid extraction method from berry seeds. The research was conducted by using these oils as the raw material for the biodegradable hydraulic working fluids. The oils were assessed in terms of kinematic viscosity, anti-wear properties, resistance to oxidation and corrosive effects to copper and the pour point. The best results were achieved in the case of the blackcurrant seed oil. In order to confirm the practical possibility of using vegetable oils as working fluids for hydraulic couplings, experimental tests of the hydrodynamic clutch filled with blackcurrant seed oil were carried out. Based on the obtained research results, it was found that oils from berry plant seeds produced by supercritical extraction could be used in the future as potential working fluids for hydraulic systems.


Lubricants ◽  
2020 ◽  
Vol 8 (12) ◽  
pp. 102
Author(s):  
Pawan Panwar ◽  
Paul Michael ◽  
Mark Devlin ◽  
Ashlie Martini

Many application-relevant fluids exhibit shear thinning, where viscosity decreases with shear rate above some critical shear rate. For hydraulic fluids formulated with polymeric additives, the critical shear rate is a function of the molecular weight and concentration of the polymers. Here we present a model for predicting the critical shear rate and Newtonian viscosity of fluids, with the goal of identifying a fluid that shear thins in a specific range relevant to hydraulic pumps. The model is applied to predict the properties of fluids comprising polyisobutene polymer and polyalphaolefin base oil. The theoretical predictions are validated by comparison to viscosities obtained from experimental measurements and molecular dynamics simulations across many decades of shear rates. Results demonstrate that the molecular weight of the polymer plays a key role in determining the critical shear rate, whereas the concentration of polymer primarily affects the Newtonian viscosity. The simulations are further used to show the molecular origins of shear thinning and critical shear rate. The atomistic simulations and simple model developed in this work can ultimately be used to formulate polymer-enhanced fluids with ideal shear thinning profiles that maximize the efficiency of hydraulic systems.


Author(s):  
Filipp Kratschun ◽  
Tobias Mielke ◽  
Katharina Schmitz

Cavitation in hydraulic systems leads to cavitation erosion which ultimately results in system failure [1, 2] and the reduction of the systems’ stiffness. There are three types of cavitation known: gas, vapour and pseudo cavitation [3]. In previous gas-cavitation studies enormous air release rates in hydraulic fluids have been discovered which could not be explained just by the diffusion of dissolved air through bubble’s boundary. A possible explanation is the simultaneous occurrence of vapour cavitation in conjunction with gas-cavitation. However, this requires drastic pressure drops below several Pa, which is hard to achieve in hydraulic systems. This article introduces a further hypothesis for the unexplainable air release rates as fourth type of cavitation. Technical fluids can dissolve other fluids, such as water, to a degree which evaporate at much higher pressures compared to the base fluid. Based on a standard HLP 46 hydraulic oil and water as dissolved fluid, the presented hypothesis is verified. Firstly, a phenomenological mathematical model is developed. Subsequently, a test rig is presented to prove the hypothesis.


2019 ◽  
Vol 302 ◽  
pp. 01020
Author(s):  
Jozef Nosian ◽  
Marietta Markiewicz ◽  
Romana Janoušková ◽  
Patrícia Feriancová

The aim of the present article is the construction of a device for measuring and testing hydrostatic converters and subsequent verification measurement of the proposed device. This device will allow the measurement and testing of hydraulic pumps under laboratory conditions. In our case, we will test the hydraulic pump UD–25R, which is used in hydraulic drives of agricultural machines. Last but not least, the device described in the article can be used to test individual energy carriers used in hydraulic systems. The described device can simulate conditions that occur in operation. Using verification measurements we have proved that the designed laboratory equipment is suitable for testing hydraulic components and also allows monitoring and testing of the properties of individual hydraulic fluids. The measurement will result in a change in flow rate over time.


1966 ◽  
Vol 39 (4) ◽  
pp. 1178-1183 ◽  
Author(s):  
W. R. Griffin

Abstract Three technically feasible routes have now been established for preparation of linear perfluoroalkylene triazine polymers. The most advanced route is based on addition polymerization of long chain fluorocarbon dinitriles and diamidines, followed by acylation and cyclodehydration to triazine polymer. Large research samples have been made, but crosslinking to thermally stable vulcanizates is still a problem. An alternate method, active halogen elimination from a difunctional fluorotriazine monomer, has been, demonstrated. High molecular weight polymer has been formed, but it is not elastomeric at room temperature. The low temperature flexibility is a function of structure and not of the method of polymerization, therefore other monomers with longer fluoroalkyl groups hold promise of elastomeric products. The route has attractive economics, but elastomeric products with crosslinking capability must be demonstrated. Coupling of diiodofluoroalkyl triazine monomers employing ultraviolet radiation has been demonstrated. This route is not being pursued because of research required and the predicted high cost of monomer preparation, when compared to the previous two routes. Evaluations of compounded vulcanized triazine elastomer show excellent resistance to hydrocarbon fuels and hydraulic fluids at 370° C and to long term air aging at 300° C. Tensile strength is in the 500 psi range, but is expected to improve with closer control of molecular weight and branching of the polymer. Excellent prospects are in view for fuel tank sealants, wire insulation and elastomer components for hydraulic systems useful in the 300° to 400° C range.


Author(s):  
L. Labanauskas ◽  
D. Bražinskienė ◽  
A. Strakšys ◽  
S. Asadauskas

Basestock properties are crucial for hydraulic fluids, because the additive amounts are low. The formulated fluids must endure long service life under high humidity levels, elevated temperatures, exposure to various metals and intensive friction in vane pumps. Ester-based fluids have enjoyed success in higher technology hydraulic systems due to reduced operating temperature. Their basestocks are synthesized from petrochemically isomerized C9–C13 monocarboxylic acids, which are esterified to polyols, such as trimethylol propane. In this study, Medium Chain Fatty Acids (MCFA) of C10–C14 have been esterified with TMP and tested under thin film simulation study. Their stability, fluidity, volatility and other properties were comparable to those of mineral and synthetic basestocks. Environmental benefits of MCFA were clearly evident, because they can be produced not only from palm oil, but also from industrial crops crambe and camelina.


Sign in / Sign up

Export Citation Format

Share Document