| 1. |
- Berg, Sven
(författare)
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A study of sample withdrawal for lubricated systems : Part 2: practical sample withdrawal and selection of proper sampling methods
- 2001
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Ingår i: Industrial Lubrication and Tribology. - : Emerald. - 0036-8792 .- 1758-5775. ; 53:3, s. 97-108
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Tidskriftsartikel (refereegranskat)abstract
- Aims to use some of the sampling techniques and sampling routines, mentioned in Part 1 of the article, to perform practical tests to determine their differences in withdrawing samples. Uses two different types of systems, a hydraulic system and a gear system, together with some of the investigated sampling techniques. In order to find out the optimum sampling method for each of the two systems, uses a specification of requirements and a systematic approach, together with practical sample withdrawal from the two systems. For the hydraulic system, uses an on-line particle counter and bottle samples from valves, and for the gear system, applies drain-plug and vacuum pump sampling. It was found that for hydraulic systems on-line sampling is the most appropriate, if information on the elements is not required. If information on the elements is required, bottle sampling from a valve together with flushing of the valve should be performed. For the gear system no difference was seen between the samples taken with a vacuum pump and those taken from the drain-plug, and therefore an alternative method is suggested to improve the reliability of the sampling.
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| 2. |
- Berg, Sven
(författare)
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A study of sample withdrawal for lubricated systems : Part 1: Influence of flow characteristics, sampling techniques and locations
- 2001
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Ingår i: Industrial Lubrication and Tribology. - : Emerald. - 0036-8792 .- 1758-5775. ; 53:1, s. 22-31
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Tidskriftsartikel (refereegranskat)abstract
- The wear of a machine element, whether it is due to fatigue or abrasive wear, will add contaminants in the form of particulates to the system. If a machine element is starting to wear out it will produce a large amount of particles and it will finally break down. Since this can be very costly, one can establish the need to monitor the system so that one can foresee failure. There are many different ways to monitor a system, e.g. measurements of the temperature, pressure, vibrations and the degree of contamination. The purpose of contamination control is to extend the life of a component and thereby save money. When monitoring a system it is very important that the monitoring control instrument should give the right output. One important factor in achieving this is the withdrawal of a representative oil sample. In this paper an investigation of where and how to take a representative sample is performed using Stokes' law and the migration of spheres in a channel. A generalised sedimentation chart for diffe rent oils and particles is introduced. Sampling routines for proper sample withdrawal are also presented
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| 3. |
- Berg, Sven, et al.
(författare)
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Investigation of the measurement precision of oil analysis instruments, using fully formulated oils : Part 2: Contamination-measuring instruments
- 2011
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Ingår i: Industrial Lubrication and Tribology. - : Emerald. - 0036-8792 .- 1758-5775. ; 63:6, s. 412-419
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Tidskriftsartikel (refereegranskat)abstract
- Purpose - The aim of this study is to determine the variation of the different oil analysis instruments in terms of standard deviation and CV-values, when measuring samples of fully formulated hydraulic and gear oils taken from working systems. Design/methodology/approach - In this investigation two different spectrometric techniques, ICP-OES and RDE-OES, have been studied to determine the instruments' precision of measurement and ability to measure the absolute level of contamination. Findings - The ICP has better precision of measurement of the two instruments, but cannot predict the absolute values of contamination when oil samples are only treated by organic solvent dilution if the samples include large or dense particles. It is therefore not too good, with the sample pre-treatment method used, at detecting wear processes that produce dense/large particles, such as pitting failure. For instance, microwave-assisted acid digestion could be used for sample pre-treating to obtain accurate results in that case. It should, however, be able to detect wear mechanisms that produce small particles such as abrasive wear in any case: the ICP has a repeatability value of ITr/IT=3 per cent and a reproducibility value of ITR/IT=12 per cent for contamination levels of between 50-400 PPM and ITr/IT=0.6 PPM and ITR/IT=2 PPM, respectively, at values below 50 PPM; the RDE cannot predict the absolute value of contamination if this includes large or dense particles if proper sample pre-treatment is not used. It is therefore not good at detecting wear mechanisms that produce dense/large particles (if the oil samples are not pre-treated properly) such as pitting but should be able to detect abrasive wear and similar processes that produce small particles in any case; the RDE's precision of measurement is not as good as the ICP, with a reproducibility variation of ITR/IT=ITr/IT=25 per cent for contamination levels between 20-500 PPM and ITR/IT=ITr/IT=6 PPM for contamination level below 20 PPM. Research limitations/implications - Measuring only on fully formulated oils from hydraulic and gear systems. Practical implications - The study will be of significant support regarding industrial interpretation of measurement results from the most common oil particle measurement methods. Originality/value - No other similar studies are known
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| 4. |
- Berg, Sven, et al.
(författare)
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Investigation of the measurement precision of oil analysis instruments, using fully formulated oils : Part 1: Spectroscopic instruments
- 2011
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Ingår i: Industrial Lubrication and Tribology. - : Emerald. - 0036-8792 .- 1758-5775. ; 63:6, s. 404-411
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Tidskriftsartikel (refereegranskat)abstract
- Purpose - The aim of this study is to determine the variation of the different oil analysis instruments in terms of standard deviation and CV-values, when measuring samples of fully formulated hydraulic and gear oils taken from working systems. Design/methodology/approach - In this investigation, two different spectrometric techniques, inductively coupled plasma-optical emission spectrometers (ICP-OES) and rotating disk electrode-optical emission spectrometers (RDE-OES), have been studied to determine the instruments' precision of measurement and ability to measure the absolute level of contamination. The study was based on a series of measurements using artificial contamination mixed with oil. Findings - The ICP has better precision of measurement of the two instruments, but cannot predict the absolute values of contamination when oil samples are only treated by organic solvent dilution if the samples include large or dense particles. It is therefore not too good, with the sample pre-treatment method used, at detecting wear processes that produce dense/large particles, such as pitting failure. For instance, microwave-assisted acid digestion could be used for sample pre-treating to obtain accurate results in that case. It should, however, be able to detect wear mechanisms that produce small particles such as abrasive wear in any case. The ICP has a repeatability value of r=3 percent and a reproducibility value of R=12 percent for contamination levels of between 50 and 400 ppm and r=0.6 and R=2 ppm, respectively, at values below 50 ppm. The RDE cannot predict the absolute value of contamination if this includes large or dense particles if proper sample pre-treatment is not used. It is therefore not good at detecting wear mechanisms that produces dense/large particles (if the oil samples are not pre-treated properly) such as pitting but should be able to detect abrasive wear and similar processes that produce small particles in any case. The RDE's precision of measurement is not as good as the ICP, with a reproducibility variation of R=r=25 percent for contamination levels between 20 and 500 ppm and R=r=6 ppm for contamination level below 20 ppm. Research limitations/implications - Only the effects from lubricating oils are studied. Practical implications - This study will significantly increase the industrial knowledge concerning measurement precision in particle contamination measurement systems. Originality/value - No similar study is found
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| 5. |
- Kumar, Saurabh, et al.
(författare)
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Additives depletion and engine oil condition : a case study
- 2005
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Ingår i: Industrial Lubrication and Tribology. - : Emerald. - 0036-8792 .- 1758-5775. ; 57:2, s. 69-72
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Tidskriftsartikel (refereegranskat)abstract
- To study and estimate changes of various properties upon use of engine oil by different methods.Design/methodology/approach – By viscosity measurement, pH measurement, Fourier transform infra‐red spectroscopic analysis and UV‐Visible (Ultraviolet and visible rays) spectroscopic analysis.Findings – Some specific changes in additives of the oil upon use could be traced.Practical implications – Correct choice for additives for a particular use may enhance the oil life and also protect the engine from damage.Originality/value – The findings may be important to the lube oil producers and the users.
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| 6. |
- Kumar, Saurabh, et al.
(författare)
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Online condition monitoring of engine oil
- 2005
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Ingår i: Industrial Lubrication and Tribology. - : Emerald. - 0036-8792 .- 1758-5775. ; 57:6, s. 260-267
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Tidskriftsartikel (refereegranskat)abstract
- Purpose – Engine oil degrades in quality during its use and after certain period of time the oil needs to be changed depending upon its condition. The purpose of this paper is to design and develop an online condition monitoring device for engine oil. Design/methodology/approach – Based on the previous works in this line and some testing of used oils in the laboratory, the correlation of change in colour with other properties were identified. An optical colour sensor was then designed and developed which can transform the darkness of oil colour into electrical resistance. A series of tests were undertaken to calibrate the system for its correctness. Findings – This type of sensor provides the information about the condition of the oil and also can inform about the probable time for drain-off of the oil. Practical implications – Engine oil changes are normally done by schedules which are highly conservative and cost the user as the oil is changed when it could be still used for some time. Use of an online sensor will minimize the cost on lubricants to some extent. Originality/value – The device is of great value to the users of IC engines as it not only reduces the cost on lubricants but also informs the user about the present condition of the oil.
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| 7. |
- Li, Yiling, et al.
(författare)
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Estimation of rolling friction coefficients in a tribosystem using optical measurements
- 2018
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Ingår i: Industrial Lubrication and Tribology. - : Emerald Group Publishing Limited. - 0036-8792 .- 1758-5775. ; 70:4, s. 680-686
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Tidskriftsartikel (refereegranskat)abstract
- PurposeThis paper presents a method to measure the rolling friction coefficient in an easy and fast way. The aim is to measure the rolling friction coefficient between a small steel ball and a cylindrical aluminum surface.Design/methodology/approachAn analytical model of the tribosystem of a freely rolling ball and a cylindrical surface is established. The rolling friction coefficient is evaluated from images recorded by a high-speed camera. The coefficient between a 1.58 mm diameter steel ball and a cylindrical aluminum surface is measured. A background subtraction algorithm is used to determine the position of the small steel ball.FindingsThe angular positions of the ball are predicted using the analytical model, and good agreement is found between the experimental and theoretical results.Originality/valueAn optical method for evaluating the rolling friction coefficient is presented, and the value of this coefficient between a small steel ball and a cylindrical aluminum surface is evaluated.
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| 8. |
- Lundberg, Jan
(författare)
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Grease lubrication of roller bearings in railway waggons. Part 1: field tests and systematic evaluation to determine the optimal greases
- 2000
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Ingår i: Industrial Lubrication and Tribology. - : Emerald. - 0036-8792 .- 1758-5775. ; 52:1, s. 36-43
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Tidskriftsartikel (refereegranskat)abstract
- Describes a comprehensive field test to determine the best grease for spherical roller bearings in railway waggon wheels and increase the knowledge of grease lubrication. Nine different fully-formulated commercial greases were examined in the wheel bearings of five ore waggons, used for transporting ore commercially by railroad from the Kiruna Mine in northern Sweden to Narvik in northern Norway for shipping to foreign markets. After the end of the test period, the wear and electrical damage, as well as the rust on the bearings, were also studied. In order to find out the optimum grease for this application, draws up a specification of requirements and uses a systematic approach to development of an evaluation method that could be applied to greases in actual service.
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| 9. |
- Lundberg, Jan, et al.
(författare)
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Grease-lubrication of roller bearings in railway waggons. Part 2 : Laboratory tests and selection of proper test methods
- 2000
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Ingår i: Industrial Lubrication and Tribology. - : Emerald. - 0036-8792 .- 1758-5775. ; 52:2, s. 76-86
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Tidskriftsartikel (refereegranskat)abstract
- New, undestroyed greases of the same brands as those used in a field test, described in Part 1, were examined using conventional methods, such as the SKF V2F test, the roll stability test (ASTM D-1831), the Grease Worker (ASTM D-217), the torque test (ASTM 1478-91), bleeding measurements ( IP 121), yield stress measurements, the 4-ball test (ASTM D 2266-86), base oil viscosity measurements, thickener content and the cone penetration test (ASTM D217-88). The greases have also been tested with several new test methods developed at the University. A specification for relevant testing methods was drawn up and the connections between the tested parameters were investigated. It was found that the mechanical stability could be predicted with a combination of ASTM D-1831 and the limiting shear stress coefficient ?. This coefficient is capable of predicting wear. It was found that the bearing temperature could be predicted by using the base oil viscosity.
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| 10. |
- Lundberg, Jan, et al.
(författare)
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Handbook for grease applications
- 2000
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Ingår i: Industrial Lubrication and Tribology. - : Emerald. - 0036-8792 .- 1758-5775. ; 52:5, s. 221-232
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Tidskriftsartikel (refereegranskat)abstract
- The process of finding the ultimate grease is described in this report using an example from railway applications. This example includes steps such as a requirement list, field tests, laboratory tests and an evaluation method. The example deals with the problems discovered in a field test performed to determine the best grease for tapered roller bearings in railway wagon wheels and to increase the knowledge of grease lubrication. Seven different fully formulated commercial greases were examined in the wheel bearings of one ore wagon, used for transporting ore commercially by railway from the Kiruna Mine in northern Sweden to Narvik in northern Norway for shipping to foreign markets. The steps performed in this study are recommended in all problems associated.
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