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  • 1.
    Berg, Sven
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    A study of sample withdrawal for lubricated systems: Part 1: Influence of flow characteristics, sampling techniques and locations2001Inngår i: Industrial Lubrication and Tribology, ISSN 0036-8792, E-ISSN 1758-5775, Vol. 53, nr 1, s. 22-31Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    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

  • 2.
    Berg, Sven
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    A study of sample withdrawal for lubricated systems: Part 2: practical sample withdrawal and selection of proper sampling methods2001Inngår i: Industrial Lubrication and Tribology, ISSN 0036-8792, E-ISSN 1758-5775, Vol. 53, nr 3, s. 97-108Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    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.

  • 3.
    Berg, Sven
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Jungmar, Ulf
    Bodycote Materials Testing AB, Linköping.
    Lundberg, Jan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Vähäoja, Pekka
    Department of Mechanical Engineering, University of Oulu.
    Investigation of the measurement precision of oil analysis instruments, using fully formulated oils: Part 1: Spectroscopic instruments2011Inngår i: Industrial Lubrication and Tribology, ISSN 0036-8792, E-ISSN 1758-5775, Vol. 63, nr 6, s. 404-411Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    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

  • 4.
    Berg, Sven
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Jungmar, Ulf
    Bodycote Materials Testing AB, Linköping.
    Lundberg, Jan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Vähäoja, Pekka
    Department of Mechanical Engineering, University of Oulu.
    Investigation of the measurement precision of oil analysis instruments, using fully formulated oils: Part 2: Contamination-measuring instruments2011Inngår i: Industrial Lubrication and Tribology, ISSN 0036-8792, E-ISSN 1758-5775, Vol. 63, nr 6, s. 412-419Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    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

  • 5. Kumar, Saurabh
    et al.
    Mishra, N.M.
    Department of Applied Chemistry, Indian School of Mines, Dhanbad.
    Mukherjee, P.S.
    Department of Mechanical Engineering and Mining Machinery Engineering, Indian School of Mines, Dhanbad, Jharkhand.
    Additives depletion and engine oil condition: a case study2005Inngår i: Industrial Lubrication and Tribology, ISSN 0036-8792, E-ISSN 1758-5775, Vol. 57, nr 2, s. 69-72Artikkel i tidsskrift (Fagfellevurdert)
  • 6. Kumar, Saurabh
    et al.
    Mukherjee, M.S.
    Department of Mechanical Engineering and Mining Machinery Engineering, Indian School of Mines, Dhanbad, Jharkhand.
    Mishra, N.M.
    Department of Applied Chemistry, Indian School of Mines, Dhanbad.
    Online condition monitoring of engine oil2005Inngår i: Industrial Lubrication and Tribology, ISSN 0036-8792, E-ISSN 1758-5775, Vol. 57, nr 6, s. 260-267Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    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.

  • 7.
    Li, Yiling
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Strömningslära och experimentell mekanik.
    Xi, Yinhu
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Shi, Yijun
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Estimation of rolling friction coefficients in a tribosystem using optical measurements2018Inngår i: Industrial Lubrication and Tribology, ISSN 0036-8792, E-ISSN 1758-5775, Vol. 70, nr 4, s. 680-686Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Purpose

    This 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/approach

    An 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.

    Findings

    The angular positions of the ball are predicted using the analytical model, and good agreement is found between the experimental and theoretical results.

    Originality/value

    An 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.

  • 8. Lundberg, Jan
    Grease-lubrication of roller bearings in railway waggons. Part 1: Field tests and systematic evaluation to determine the optimal greases2000Inngår i: Industrial Lubrication and Tribology, ISSN 0036-8792, E-ISSN 1758-5775, Vol. 52, nr 1, s. 36-43Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    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.

  • 9. Lundberg, Jan
    et al.
    Berg, Sven
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Grease-lubrication of roller bearings in railway waggons. Part 2: Laboratory tests and selection of proper test methods2000Inngår i: Industrial Lubrication and Tribology, ISSN 0036-8792, E-ISSN 1758-5775, Vol. 52, nr 2, s. 76-86Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    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.

  • 10. Lundberg, Jan
    et al.
    Berg, Sven
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Handbook for grease applications2000Inngår i: Industrial Lubrication and Tribology, ISSN 0036-8792, E-ISSN 1758-5775, Vol. 52, nr 5, s. 221-232Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    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.

  • 11. Norrby, Thomas
    Environmentally adapted lubricants: where are the opportunities?2003Inngår i: Industrial Lubrication and Tribology, ISSN 0036-8792, E-ISSN 1758-5775, Vol. 55, nr 6, s. 268-274Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Environmentally adapted lubricants (EALs) have been a slowly growing segment of the lubricants business since the early 1970s. The evolution of environmental thinking has led to the change of focus, from biodegradability to renewability. In the future, the focus will be more on fuel economy and lower emissions. Technical development drivers include the availability of suitable base fluids and additives for lubricants formulation and the adaptation of technical standards, OEM specifications and eco-labels. Important non-technical development drivers include environmental management tools and eco auditing. Environmental policy, and procurement guidelines for cities and government organizations, clearly has a large impact. EALs have been repeatedly heralded as one of the few future growth segments of the lubricants business, hence the relatively large increase in R&D activity over the last decade. In sales terms, growth has been slow, limited by high cost and several other factors. For a good future development, both technical and political hurdles must be overcome.

  • 12. Norrby, Thomas
    et al.
    Kopp, M.
    Torbacke, M.
    Environmentally adapted lubricants in the Nordic marketplace: recent developments2002Inngår i: Industrial Lubrication and Tribology, ISSN 0036-8792, E-ISSN 1758-5775, Vol. 54, nr 3, s. 109-116Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The Nordic marketplace, and in particular the Swedish market, is a sizeable part of the world market for environmentally adapted lubricants (EALs). The largest segment, by far, is EAL hydraulic fluids for mobile hydraulics, and chain saw oils for the environmentally adapted forestry operations (mainly) by the international Swedish and, until recently, Finnish forestry companies. In this paper, some of the important parameters influencing the size and development direction are analysed. These include market regulatory factors, eco-labels, OEM-issued standards/specifications, end-user demands and the market volume development for the period 1999-2001. The spread of EALs to other forestry markets, Norway and the Baltic States, is also covered.

  • 13. Norrby, Thomas
    et al.
    Kopp, Milan
    Environmentally adapted lubricants in Swedish forest industry: a critical review and case study2000Inngår i: Industrial Lubrication and Tribology, ISSN 0036-8792, E-ISSN 1758-5775, Vol. 52, nr 5, s. 116-125Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    During the last ten years, a gradual conversion from mineral oil based hydraulic fluids to environmentally adapted lubricants (EALs), has taken place in the forest industry in Sweden. The current market share of the EALs is ca. 80 percent of the mobile hydraulic fluids utilised. The original driving force of this change can be traced to end-user demands, especially paper and pulp consumers in Germany. The Swedish standard SS 15 54 34 was in 1997 supplemented with environmental criteria derived from the "Ren Smörja" ("Clean Lubrication") environmental project in the city of Göteborg. The reliable third-party validation offered by SP (Swedish National Testing and Research Institute), the present stewards of the "Clean Lubrication" list, has proven to be another important factor. By comparison to the German Blue Angel Eco-labelling scheme, the Swedish SP-list approval is somewhat easier to attain, and has provided a flexible base for the development of new products.

  • 14.
    Rosenkrantz, Andreas
    et al.
    Department of Material Science and Engineering, Institute of Functional Materials, Saarland University, Saarbruecken, Germany.
    Khan, Saad Ahmed
    Department of Material Science and Engineering, Institute of Functional Materials, Saarland University, Saarbruecken, Germany.
    Szurdak, Adam
    Institute of Metal Forming, RWTH Aachen University, Aachen, Germany.
    Hirt, Gerhard
    Institute of Metal Forming, RWTH Aachen University, Aachen, Germany.
    Gachot, Carsten
    Department of Material Science and Engineering, Saarland University, Saarbrücken, Germany.
    Wear behavior of micro-coined steel surfaces under mixed lubrication2017Inngår i: Industrial Lubrication and Tribology, ISSN 0036-8792, E-ISSN 1758-5775, Vol. 69, nr 6, s. 1033-1039Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Purpose - The purpose of this study is to investigate the influence of hemispherical structures fabricated by hot micro-coining on the resulting wear performance. Hemispherical structures with different area densities (20 and 30 per cent), depths (50 and 100 mu m) and diameters (100 and 200 m) were fabricated by hot micro-coining on stainless steel samples.

    Design/methodology/approach - The wear performance of these samples was studied using a ball-on-disk tribometer in rotational sliding mode using a normal load of 30 N and a fixed sliding velocity of 2 cm/s. Two different poly-(alpha)-olefin (PAO) oils without any additive having a kinematic viscosity of 4 and 40 cSt, were used to study the influence of the oil viscosity on the wear behavior.

    Findings - Concerning the polished reference, an enlarged wear volume with an increase in the cycle number and the oil viscosity was observed. In the case of the micro-coined surfaces, all samples demonstrate a pronounced reduction in the wear volume (up to a factor of 100 for PAO 40) compared to the polished reference irrespective of the oil viscosity used.

    Originality/value - This study details new research work studying the wear behavior of hot micro-coined surfaces.

  • 15.
    Tuomas, Roger
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Isaksson, Ove
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Produkt- och produktionsutveckling.
    Measurement of lubrication conditions in a rolling element bearing in a refrigerant environment2009Inngår i: Industrial Lubrication and Tribology, ISSN 0036-8792, E-ISSN 1758-5775, Vol. 61, nr 2-3, s. 91-99Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Purpose - The ability to build up a film thickness separating the contacts in the bearing is essential to assure long service life of rolling element bearings. Rolling element bearings used in refrigeration suffer from poor film thickness due to decreased viscosity of the lubricant by the dilution of refrigerant in the oil. The purpose of this paper is to redesign a bearing test apparatus equipped with a capacitance measuring device able to monitor the lubrication status in the bearing online and include experiments to verify the capacitance measuring technique. Design/methodology/approach - The objective is to design a complete system to study film build up in rolling element bearings in a refrigerant environment and to use and evaluate the capacitance/resistance measuring technique.Findings - The investigation shows good correlation between denting on tested bearings and the identified contacts by the capacitance measuring apparatus. The method is also useful when studying lift-off or run-in of a bearing.Originality/value - in this paper, a bearing test apparatus is redesigned and equipped with a capacitance measuring device

  • 16. Waara, Patric
    Lubricant influence on flange wear in sharp railroad curves2001Inngår i: Industrial Lubrication and Tribology, ISSN 0036-8792, E-ISSN 1758-5775, Vol. 53, nr 4, s. 161-168Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Since the middle of the 1970s, lubrication of the high rail flange has been used to reduce wear rates. Field tests have been taking place since 1997 to evaluate the differences in wear characteristics between mineral oil based grease and new environmentally adapted greases. The field tests have also investigated whether the addition of graphite contributed to reduced flange wear. The wear reducing effect of trackside lubrication as a function of distance from point of application of the grease was also investigated. The field tests showed that environmentally adapted greases can be used without risk of increased rail wear and that the addition of solid lubricants, such as graphite, has no significant effect on the rate of wear. The highest wear rates were found during winter months when active lubrication stops due to problems associated with the sub-zero temperatures common in northern Sweden. Year-round lubrication would be expected to decrease wear rates significantly.

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