scholarly journals Analysis of grease contamination influence on the internal radial clearance of ball bearings by thermographic inspection

2016 ◽  
Vol 20 (1) ◽  
pp. 255-265 ◽  
Author(s):  
Zarko Miskovic ◽  
Radivoje Mitrovic ◽  
Zoran Stamenic
Keyword(s):  
Service Life ◽  
Working Conditions ◽  
Solid Particles ◽  
Experimental Methodology ◽  
Open Pit ◽  
Radial Clearance ◽  
Ball Bearings ◽  
High Concentration ◽  
Experimental Data Processing ◽  
Mathematical Correlation

One of the most important factors influencing ball bearings service life is its internal radial clearance. However, this parameter is also very complex because it depends on applied radial load and ball bearings dimensions, surface finish and manufacturing materials. Thermal condition of ball bearings also significantly affects internal radial clearance. Despite many researches performed in order to find out relevant facts about different aspects of ball bearings thermal behaviour, only few of them are dealing with the real working conditions, where high concentration of solid contaminant particles is present. That?s why the main goal of research presented in this paper was to establish statistically significant correlation between ball bearings temperatures, their working time and concentration of contaminant particles in their grease. Because of especially difficult working conditions, the typical conveyor idlers bearings were selected as representative test samples and appropriate solid particles from open pit coal mines were used as artificial contaminants. Applied experimental methodology included thermographic inspection, as well as usage of custom designed test rig for ball bearings service life testing. Finally, by obtained experimental data processing in advanced software, statistically significant mathematical correlation between mentioned bearings characteristics was determined and applied in commonly used internal radial clearance equation. That is the most important contribution of performed research - the new equation and methodology for ball bearings internal clearance determination which could be used for eventual improvement of existing bearings service life equations.

Filtering of High Solids Concentration Media Using Complex Powerful to the Flow

2021 ◽  
Vol 9 (2) ◽  
pp. 49-53
Author(s):  
Vladimir Devisilov ◽  
E. Sharay ◽  
I. Myagkov
Keyword(s):  
Service Life ◽  
High Viscosity ◽  
Solid Particles ◽  
Oil Refining ◽  
Flow Section ◽  
Regeneration Ability ◽  
Sediment Layer ◽  
Centrifugal Forces ◽  
Design Development ◽  
High Concentration

Currently, intensification of the filtering processes in media characterized by high concentration of solid particles remains of great interest in many sectors, such as oil production, oil refining, chemical, medical and food industries. One of the reasons that impede filtering could be the high viscosity level of the dispersion medium. It is known that the filtering rate is inversely proportional to viscosity; therefore, filtering of viscous liquids would be carried out much slower. In addition, filtering media characterized by high concentration of solid particles leads to higher costs for creating the process driving force, fast pores fouling in the filtering material and the need for frequent regeneration of the filtering material. Many media characterized by high viscosity, such as mineral oils, polymer solutions and melts, heavily polluted waters tend to reduce the flow section of the porous material channel; and, as a result, hydraulic characteristics are changing and regeneration of the filtering material is hampered. Therefore, replacement of the filtering material is required, which increases the costs. It is possible to intensify the filtering process by ensuring the suspension preliminarily preparing, for example, by increasing the medium temperature or decreasing the suspension viscosity, as well as adding a suitable solvent. In many technological processes such methods are unacceptable. Design, development and study of devices that allow increasing the filtering material service life and reducing energy consumption to create the required pressure gradient while maintaining the device compactness and ensuring the required fineness of filtration still remains a topical task. This paper is proposing to use filtering in combination with cleaning in centrifugal and vibration fields created in hydrodynamic filters. Centrifugal forces field in the hydrodynamic filter is formed due to liquid tangential introduction into the apparatus and rotation of the cylindrical porous filter partition. The method differs from other technologies by creating a potential flow in the apparatus annular zone within the centrifugal forces field. Such flow organization allows purging up to 80% of polluting substances from the media under cleaning by the centrifugal force mechanism; and such substances are removed from the filter without deposition on the filter partition. This would reduce the load on filter material and increase its service life. Vibration of the filtering partition provided for in its structure makes it possible to destroy the sediment layer thereon and to direct the sediment into the filtrate flow. Thus, the proposed hydrodynamic filter is provided with the self-regeneration ability.

Management and engineering solutions to improve stripping equipment efficiency in Chernogorksy open pit mine

2018 ◽  
pp. 36-48
Author(s):  
G. N. Shapovalenko ◽  
S. N. Radionov ◽  
V. V. Gorbunov ◽  
V. A. Khazhiev ◽  
V. Yu. Zalyadnov ◽  
...  
Keyword(s):  
Open Pit Mine ◽  
Open Pit ◽  
High Concentration ◽  
Open Pit Mines ◽  
Blasting Operation ◽  
Internal Dump ◽  
Mining Conditions ◽  
Mining Front ◽  
Comparison Of Equipment

Chernogosky open pit mine integrates truck-and-shovel system of mining with overburden rehandling to internal dump with a set of walking excavators for rehandling of overburden to mined-out area of the pit. It is possible to improve efficiency of stripping in the conditions of Chernogorsky OPM by reducing percentage of stripping with more expensive handling system. The relevant research and solutions to this effect are presented in this article. Comparative characterization of mining conditions and parameters of mining systems applied is given for open pit mines Chernogorsky, Turnui, Nazarovsky, Vostochno-Beisky and Izykh. The comparative analysis points at the need to account for difficulty of mining and process sites in comparison of equipment productivity. High concentration of mining machines, which is conditioned by narrow mining front and simultaneous operation of five faces, as well as blasting operation implemented every 1-2 days, are recognized as the main constraints of excavator capacity in mining with direct dumping in Chernogorsky open pit mine. The management and engineering solutions implemented in the mine and resulted in higher efficiency of draglines are described.

Film Elasticity and Film Stabilization in Firefighting Foam Stabilized by Solid Particles

2017 ◽  
Vol 744 ◽  
pp. 346-349
Author(s):  
Xiu Juan Li ◽  
Rui Song Guo ◽  
Min Zhao
Keyword(s):  
Life Time ◽  
Liquid Films ◽  
Thin Liquid Films ◽  
Solid Particles ◽  
High Concentration ◽  
Hydration Effect ◽  
Fixed Area ◽  
The Stability ◽  
Hydration Layers ◽  
Hydration Forces

The structure of the thin liquid films determines the stability of foams and emulsions. In this work the bubbles stretched length with different hollow SiO2 particles concentration is measured when the foam has been stilled for different time. The results show that the bubbles stretched length is longer than that of bubbles when the foam is free of hollow SiO2 particles even when the foam has been stilled for 500mins. The bubbles stretched length increases with increasing the concentration of hollow SiO2 particles. A strong hydration effect leaves a large volume of hydration layers on the solid particles surfaces in aqueous solutions. The water in hydration layers can help the film keep a certain thickness. The existence of hydration forces leads that two particles cannot be too close each other. The high concentration surfactant limited in the fixed area helps the film keep good elasticity. Therefore the film has a long life time with compatible thickness and elasticity and the three-phrase foam is upper stable.

Preload-service life correlation for ball bearings on machine tool main spindles

Wear ◽  
1994 ◽  
Vol 172 (1) ◽  
pp. 79-83 ◽  
Author(s):  
G.D. Hagiu ◽  
M.D. Gafitanu
Keyword(s):  
Service Life ◽  
Machine Tool ◽  
Ball Bearings

The Influence of the Leading Wheel Structural Change on Stress of Multi-Rope Friction Hoist

2013 ◽  
Vol 670 ◽  
pp. 48-53 ◽  
Author(s):  
Guang Lin Zhou ◽  
W.J. Chu
Keyword(s):  
Finite Element ◽  
Structural Change ◽  
Service Life ◽  
Working Conditions ◽  
Weld Bead ◽  
Rational Structure ◽  
Open Problems ◽  
Finite Element Software ◽  
Stress Fluctuation

To avoid the open problems of the leading wheel and get a more rational structure, the paper uses PRO / E and the finite element software to analyze the leading wheel of JKM-3.25/4 multi-rope friction hoist. The results show that in the leading wheel the rib plates between the channel steel and wheel hub are removed or added the same ones will have little effect on the overall force situation, and only affect the stress of the weld bead. To solve the problem of open weld of rib plates, can consider the rib plates to be removed. When the radial angle between support wheel and drum is bigger than 6°, the overall force of the leading wheel is affected seriously. But when the radial angle is 5°, the amplitude of stress fluctuation is the minimum, which can improve the leading wheel working conditions and increase the service life of the leading wheel. Therefore the suggestion is to take the radial angle of 5° when to design the new multi-rope hoist. Study conclusions provide the theoretical supports for the leading wheel of multi-rope friction design and technical renovation.

scholarly journals STUDY OF EFFECT OF SOLID CONTAMINANTS IN THE LUBRICANT ON BALL BEARINGS VIBRATION

2012 ◽  
pp. 28-31
Author(s):  
ONKAR L. MAHAJAN ◽  
ABHAY A. UTPAT
Keyword(s):  
Experimental Tests ◽  
Solid Particles ◽  
Particle Sizes ◽  
Ball Bearings ◽  
Bearing Failure ◽  
Mean Square ◽  
Rolling Bearings ◽  
Vibration Signals ◽  
Deep Groove ◽  
Concentration Levels

In deep groove ball bearings contamination of lubricant grease by solid particles is one of the main reason for early bearing failure. To deal with such problem, it is fundamental not only the use of reliable techniques concerning detection of solid contamination but also the investigation of the effects of certain contaminant characteristics on bearing performance. Nowadays the techniques such as vibration measurements are being increasingly used for on-time monitoring of machinery performance. The present work investigates the effect of lubricant contamination by solid particles on the dynamic behavior of rolling bearings, in order to determine the trends in the amounts of vibration affected by contamination in the Grease and by the bearing wear itself. Experimental tests are performed with Deep-groove ball bearings. The Dolomite powder in three concentration levels and different particle sizes was used to contaminate the grease. Vibration signals were analyzed in terms of Root Mean Square (RMS) values and also in terms of defect frequencies.

Corrosion of Amorphous Fe73.5Si13.5B9Nb3Cu1 Alloys on the Synergistic Effect of Chloride and Hydroxyl Ions

2011 ◽  
Vol 284-286 ◽  
pp. 1550-1553
Author(s):  
Ming Sheng Li ◽  
Dan Zhang ◽  
Yi Ming Jiang ◽  
Jin Li
Keyword(s):  
Magnetic Properties ◽  
Electrochemical Impedance Spectroscopy ◽  
Sodium Chloride ◽  
Impedance Spectroscopy ◽  
Service Life ◽  
Corrosion Rate ◽  
Electrochemical Impedance ◽  
Soft Magnetic Properties ◽  
High Concentration ◽  
Soft Magnetic

The soft-magnetic properties and service life of amorphous or nanocrystalline Fe73.5Si13.5B9Nb3Cu1 have been influenced by the corrosion of the alloy. In this study, the electrochemical corrosions of amorphous Fe73.5Si13.5B9Nb3Cu1 in the blend solutions of sodium chloride and sodium hydroxide were investigated by linear polarization (PLZ) and electrochemical impedance spectroscopy (EIS) technique. The presence of OH- in the blend solution gave rise to typical passivation of the alloy. A suitable concentration of OH- was required for the low corrosion rate. And the higher concentration of OH- led to a faster corrosion. Increase of concentration of Cl- aroused more obvious corrosion. These results were ascribed to the deteriorating effect of Cl- and high-concentration OH- on the passive film formed on the surface of amorphous Fe73.5Si13.5B9Nb3Cu1.

Dynamic Measurement of Bearing Radial Clearances

2005 ◽  
Vol 295-296 ◽  
pp. 361-366 ◽  
Author(s):  
Yu Xue Chen ◽  
S.N. Yang
Keyword(s):  
Measurement Accuracy ◽  
Systematic Errors ◽  
Dynamic Measurement ◽  
Outer Ring ◽  
Radial Clearance ◽  
Test Time ◽  
Ball Bearings ◽  
Test Results ◽  
Accuracy Measures

Outer ring tilted or offset axially, caused by improperly fixing relatively to the inner ring, will produce remarkable systematic errors in measured radial clearance of a bearing. Analyzing their effects in detail on the results of measured radial clearances, they are found to be the main sources affecting the measurement accuracy. Measures for removing them are proposed. Based on these, a novel type of instrument for measurement of radial clearances of ball bearings has been developed. It could avoid the two kinds of systematic errors. The measuring principle, structures and working procedures of the instrument are presented. Test results show that the test time is less than 15 seconds per a part and the indication stability is between ±1.0 µm.

Dynamics of water, hydrated-ions and charged polymers in highly-confined films, and their role in friction modification

2003 ◽  
Vol 790 ◽  
Author(s):  
Jacob Klein ◽  
Uri Raviv ◽  
Susan Perkin ◽  
Nir Kampf ◽  
Suzanne Giasson
Keyword(s):  
Polymer Brushes ◽  
Aqueous Media ◽  
Free Water ◽  
Aqueous Salt Solution ◽  
Ball Bearings ◽  
High Concentration ◽  
Charged Surfaces ◽  
Hydrated Ions ◽  
Charged Polymer ◽  
The One

ABSTRACTRecent studies have revealed that, in contrast to non-associating liquids such as oils or organic solvents, salt-free water retains a viscosity close to its bulk value even when confined to films thinner than some 3 nm, indeed down to only one or two monolayers thick [1,2]. For the case of high concentration aqueous salt solution compressed down to subnanometer films between charged surfaces, the trapped hydrated ions serve to act as molecular ball-bearings, sustaining a large load while remaining very fluid under shear [3]. This behaviour is attributed to the tenacity of the hydration sheaths together with their rapid relaxation time. Finally, a very recent study [4] has shown that when charged polymer brushes in aqueous media are compressed and slid past each other, they provide a lubrication that is considerably superior to that afforded by neutral brushes: This is attributed on the one hand to the resistance to mutual interpenetration of the chains due to entropic barriers in the good-solvent conditions, and, on the other hand, to the hydration-sheaths on the charged polymer segments which can act – as noted above – as molecular ball-bearings.

Operational performance analysis of spiral capsule robot in multiphase fluid

Robotica ◽  
2018 ◽  
Vol 37 (2) ◽  
pp. 213-232
Author(s):  
Liang Liang ◽  
Bai Chen ◽  
Yong Tang ◽  
Yan Xu ◽  
Yu Liu
Keyword(s):  
Performance Indicators ◽  
Thrust Force ◽  
Optimization Method ◽  
Solid Particles ◽  
Operational Performance ◽  
Maximum Pressure ◽  
High Concentration ◽  
Two Phase ◽  
Axial Thrust ◽  
Mixed Fluid

SUMMARYMinimally invasive surgery is a developing direction of modern medicine. With the successful development of controllable capsule endoscopies, capsule robots are very popular in the field of gastrointestinal medicine. At present, the study of intestinal robots is aimed at the pipeline environment of a single-phase liquid flow. But there exist food residues (i.e. solid particles) or liquid foods in the actual intestine, so intestinal fluid should be liquid–solid or liquid–liquid two-phase mixed fluid. For inner spiral capsule robots with different internal diameters and outer spiral capsule robots, using computational fluid dynamics (CFD) method, the operational performance indicators (i.e. axial thrust force, circumferential resisting moment and maximum pressure to pipeline wall) of spiral capsule robots are numerically calculated in the liquid–solid or liquid–liquid two-phase mixed fluid. By the orthogonal experimental optimization method, the optimum design of spiral capsule robots is obtained in the liquid–solid mixed fluid. The experimental verification has been also carried out. The results show that in the liquid–solid two-phase fluid, the axial thrust force and circumferential resisting moment of the spiral capsule robots decrease with the increase of the size or concentration of solid particles. In the same liquid–solid or liquid–liquid mixed fluid, the operational performance indicators of outer spiral robots are much higher than those of inner spiral robots, and the operational performance indicators of inner spiral robots with bigger internal diameters are higher than those with smaller internal diameters. Adding solid particles of high concentration in the pipeline containing liquid will reduce the drive performance of spiral capsule robots, but adding another liquid of high viscosity will improve the drive performance of spiral capsule robots.

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