Vibration and oil analysis for monitoring problems related to water contamination in rolling

Trying to reduce particle contamination in lubrication systems, industries of the whole world spend millions of dollars each year on the improvement of filtration technology. In this context, by controlling fluid cleanliness, some companies are able to reduce failures rates up to 85 percent. However, in some industries and environments, water is a contaminant more frequently encountered than solid particles, and it is often seen as the primary cause of component failure. Only one percent of water in oil is enough to reduce life expectancy of a journal bearing by 80 percent. For rolling bearing elements, the situation is worse because water destroys the oil film and, under the extreme temperatures and pressures generated in the load zone of a rolling bearing element, free and emulsified water can result in instantaneous flash-vaporization giving origin to erosive wear. This work studies the effect of water as lubricant contaminant in ball bearings, which simulates a situation that could actually occur in real systems. In a designed bench test, three basic lubricants of different viscosities were contaminated with different contents of water. The results regarding oil and vibration analysis are presented for different bearing speeds.

Maintenance of a reducer by vibration and wear particles analysis

Purpose - The purpose of the paper is to provide information on wear debris on oil and vibration analysis as predictive maintenance techniques in reducer. Design/methodology/approach - The estate of a reducer is verified by analyzing the vibration and oil conditions of a test rig under well-designed conditions utilizing some predictive variables. Findings - According to the vibration and oil analysis it is found out what it was happening into the reducer without disassembling it. Practical implications - This paper demonstrates the use of oil debris analysis and vibration analysis as a technique that enhances preventive maintenance practices. The paper helps practitioners to utilize these techniques more effectively. Originality/value - This paper gives information about two predictive maintenance techniques with a test rig. © Emerald Group Publishing Limited.

Vibration and wear particles analysis in a test stand

Purpose - This paper aims to provide information on wear debris on oil and vibration analysis as predictive maintenance techniques. Design/methodology/ approach - The estate of a reducer is verified by analyzing the vibration and oil conditions of a test rig under some variables. Findings - According to the vibration and oil analysis it was found what was happening in the reducer without disassembling it. Originality/value - This paper gives information about two predictive maintenance techniques with a test rig. © Emerald Group Publishing Limited.

Dietary fish oil replacement with lard and soybean oil affects triacylglycerol and phospholipid muscle and liver docosahexaenoic acid content but not in the brain and eyes of surubim juveniles Pseudoplatystoma sp

Triplicate groups of juvenile suribim were fed for 183 days one of four different isonitrogenous (47.6% crude protein) and isolipidic (18.7% lipid) diets formulated using three different lipid sources: 100% fish oil (FO, diet 1); 100% pig lard (L, diet 2); 100% soybean oil (SO, diet 3), and FO/L/SO (1:1:1, w/w/w; diet 4). The tissue levels of fatty acids 18:2n - 6 and 18:3n - 3 decreased relative to corresponding dietary fatty acid values. The 20:5n - 3 and 22:6n - 3 composition of muscle and liver neutral lipids were linearly correlated with corresponding dietary fatty acid composition. In contrast, the 22:6n - 3 composition of the brain and eye were similar among treatments. The 22:6n - 3 level was enriched in all tissues, particularly in the neural tissues. Similar results were observed for tissue polar lipids: fatty acids content reflected dietary composition, with the exception of the 22:6n - 3 level, which showed enrichment and no differences between groups. Given these results, the importance of the biochemical functions (transport and/or metabolism) of 22:6n - 3 in the development of the neural system of surubim warrants further investigation. © Springer Science+Business Media B.V. 2008.

Catalytic pyrolysis of agricultural residues for bio-oil production

Agricultural residues from Thailand, namely stalk and rhizome of cassava plants, were employed as raw materials for bio-oil production via fast pyrolysis technology. There were two main objectives of this project. The first one was to determine the optimum pyrolysis temperature for maximising the organics yield and to investigate the properties of the bio-oils produced. To achieve this objective, pyrolysis experiments were conducted using a bench-scale (150 g/h) reactor system, followed by bio-oil analysis. It was found that the reactor bed temperature that could give the highest organics yield for both materials was 490±15ºC. At all temperatures studied, the rhizome gave about 2-4% higher organics yields than the stalk. The bio-oil derived from the rhizome had lower oxygen content, higher calorific value and better stability, thus indicating better quality than that produced from the stalk. The second objective was to improve the bio-oil properties in terms of heating value, viscosity and storage stability by the incorporation of catalyst into the pyrolysis process. Catalytic pyrolysis was initially performed in a micro-scale reactor to screen a large number of catalysts. Subsequently, seven catalysts were selected for experiments with larger-scale (150 g/h) pyrolysis unit. The catalysts were zeolite and related materials (ZSM-5, Al-MCM-41 and Al-MSU-F), commercial catalysts (Criterion-534 and MI-575), copper chromite and ash. Additionally, the combination of two catalysts in series was investigated. These were Criterion-534/ZSM-5 and Al-MSU-F/ZSM-5. The results showed that all catalysts could improve the bio-oils properties as they enhanced cracking and deoxygenation reactions and in some cases such as ZSM-5, Criterion-534 and Criterion-534/ZSM-5, valuable chemicals like hydrocarbons and light phenols were produced. The highest concentration of these compounds was obtained with Criterion-534/ZSM-5.

Previsão de avarias em transformadores de potência através da análise de ensaios físico-químicos

Os Transformadores de potência são máquinas de elevada importância ao nível dos Sistemas Elétricos de Energia (SEE) uma vez que são estas máquinas que possibilitam a interligação dos diferentes níveis de tensão da rede e a transmissão de energia elétrica em Corrente Alternada (CA). Geralmente, estas máquinas são de grandes dimensões e de elevado nível de complexidade construtiva. Caracterizam-se por possuírem períodos de vida útil bastante elevados (vinte a trinta anos) e preços elevados, o que conduz a um nível de exigência de fiabilidade muito elevada, uma vez que não e viável a existência de muitos equipamentos de reserva nos SEE. Com o objetivo de tentar maximizar o período de vida útil dos transformadores de potência e a sua fiabilidade, tenta-se, cada vez mais, implementar conceitos de manutenção preventiva a este tipo de máquinas. No entanto, a gestão da sua vida útil e extremamente complexa na medida em que, estas máquinas têm vários componentes cruciais e suscetiveis de originar falhas e, quase todos eles, encontram-se no interior de uma cuba. Desta forma, não e possível obter uma imagem do seu estado, em tempo real, sem colocar o transformador fora de serviço, algo que acarreta custos elevados. Por este motivo, desenvolveu-se uma técnica que permite obter uma indicação do estado do transformador, em tempo real, sem o retirar de serviço, colhendo amostras do óleo isolante e procedendo a sua análise físico-química e Analise Gases Dissolvidos (DGA). As análises aos óleos isolantes tem vindo a adquirir uma preponderância muito elevada no diagnóstico de falhas e na analise do estado de conservação destes equipamentos tendo-se desenvolvido regras para interpretação dos parâmetros dos óleos com carácter normativo. Considerando o conhecimento relativo a interpretação dos ensaios físico-químicos e DGA ao oleol, e possível desenvolver ferramentas capazes de otimizar essas mesmas interpretações e aplicar esse conhecimento no sentido de prever a sua evolução, assim como o surgimento de possíveis falhas em transformadores, para assim otimizar os processos de manutenção. Neste campo as Redes Neuronais Artificiais (RNAs) têm um papel fundamental

AVALIAÇÃO DAS NORMAS DE ENSAIO APLICADAS NA QUANTIFICAÇÃO DE PCBs EM ÓLEO ISOLANTE

Polychlorinated biphenyls (PCBs) were widely used between 1940 and 1970 as an insulating fluid for transformers and capacitors. However, they are bioaccumulative and potentially carcinogenic and, according to the 2001 Stockholm Convention, must be eliminated by 2025. In Brazil, they have been gradually eliminated but contaminated equipment remains. The Brazilian official standard for PCBs content in oil analysis is the ABNT NBR 13882 and there is also the IEC 61619 International Standard, both based on GC-ECD quantification. This work identified the inefficiency of these analytical methods and highlights potential failures which generated discrepancies on quantification of these contaminants. It was observed that the IEC 61619 is superior to ABNT NBR 13882 in analytical criteria, but has problems with the inefficiency of the adsorbent material used in pretreatments for removal of oxidation products from oil where these adsorbents adsorbed some PCBs molecules, causing errors in quantification.

Concentrations of free amino acids and sugars in nine potato varieties: effects of storage and relationship with acrylamide formation

Acrylamide forms during cooking and processing predominately from the reaction of free asparagine and reducing sugars in the Maillard reaction. The identification of low free asparagine and reducing sugar varieties of crops is therefore an important target. In this study, nine varieties of potato (French fry varieties Maris Piper (from two suppliers), Pentland Dell, King Edward, Daisy, and Markies; and chipping varieties Lady Claire, Lady Rosetta, Saturna, and Hermes) grown in the United Kingdom in 2009 were analyzed at monthly intervals through storage from November 2009 to July 2010. Acrylamide formation was measured in heated flour and chips fried in oil. Analysis of variance revealed significant interactions between varieties nested within type (French fry and chipping) and storage time for most free amino acids, glucose, fructose, and acrylamide formation. Acrylamide formed in chips correlated significantly with acrylamide formed in flour and with chip color. There were significant correlations between glucose or total reducing sugar concentration and acrylamide formation in both variety types, but with fructose the correlation was much stronger for chipping than for French fry varieties. Conversely, there were significant correlations with acrylamide formation for both total free amino acid and free asparagine concentration in the French fry but not chipping varieties. The study showed the potential of variety selection for preventing unacceptable levels of acrylamide formation in potato products and the variety-dependent effect of long-term storage on acrylamide risk. It also highlighted the complex relationship between precursor concentration and acrylamide risk in potatoes.

Níveis de potássio em solução nutritiva, desenvolvimento de plantas e a produção de óleo essencial de mentha piperita L

Pós-graduação em Agronomia (Horticultura) - FCA

Procedimentos de coletas de óleo para análise preditiva de turbinas à gás

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Uso da técnica de análise de óleo lubrificante em motores diesel estacionários, utilizando-se misturas de biodiesel e diferentes níveis de contaminação do lubrificante

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Análise da influência da contaminação do lubrificante por biodiesel em um equipamento Pin-on-disk

Pós-graduação em Engenharia Mecânica - FEIS

Manutenção preditiva de motores de combustão interna, à gasolina, através da técnica de análise de lubrificantes

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Monitoramento e avaliação da condição de um sistema propulsor aeronaútico através de técnicas de análise de partículas em óleos lubrificantes

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Predictive maintenance of a worm reducer with an unbalanced load

Among all predictive maintenance techniques the oil analysis and vibration analysis are the most important for monitoring some mechanical systems. The integration of these techniques has potential to improve industrial maintenance practices and provide a better economic gain for industries. To study the integration of these two techniques, a test rig was set up to obtain an extreme working condition for the worm reducer used in this paper. The test rig was composed by a motor connected to a reducer through a flexible coupling and with an unbalanced load. The analysis of the results carried out by using a sample of the oil recommended by the manufacturer in extreme conditions, and using liquid contaminant is presented. From the results it was observed that if there is an abnormal instantaneous load in a system, the subsequent vibration analysis may not perceive what occurred if there was no permanent damage, which is not the case with the lubricant analysis.