Wyniki wyszukiwania - BazTech

1

Analysis of the influence of hydraulic fluid quality on external gear pump performance

Novaković Borivoj, Radovanović Ljiljana, Zuber Ninoslav, Radosav Dragica, Đorđević Luka, Kavalić Mila

Eksploatacja i Niezawodność

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2022

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Vol. 24, no. 2

260--268

EN

The basis of every hydraulic system is based on energy transformations, which are realized through hydraulic working fluid. Hydraulic oils are certainly subject to changes within their structure, meaning the basic characteristics and parameters of hydraulic oil, such as density, viscosity, humidity. The oils that are exploited are exposed to the process of degradation, which largely leads to significantly poorer quality of hydraulic fluid. The paper deals with the influence of changes in the characteristics of the hydraulic fluid on the hydraulic operating parameters of the gear pump installed on the hydraulic press. The parameters refer to pressure, flow, and temperature, as well as the quality of hydraulic oil, which affects the volumetric efficiency of the pump, and the results presented in the conclusion are based on the measured values of parameters before and after corrective measures. The control of parameters aims to increase the efficiency and reliability of the hydraulic system, a way of modern detection of deviations of parameters from standard, required values.

2

The analysis of influential parameters on calibration and feeding accuracy of belt feeders

Živanić Dragan, Ilanković Nikola, Zuber Ninoslav, Đokić Radomir, Zdravković Nebojš, Zelić Atila

Eksploatacja i Niezawodność

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2021

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Vol. 23, no. 3

413--421

EN

Continual material feeding represents a process of great importance for process industries. Feeding with belt feeders represents one of the most common methods. Belt feeders are devices that require little space, they are not expensive and, most importantly, they do not interrupt material flow while feeding. Calibration of belt feeders, as well as other measuring devices, is a prerequisite for measuring and achieving a defined level of measurement accuracy. On the other hand, the defined level of measurement accuracy is often difficult to achieve in practice due to the multitude of factors that affect the operation of belt feeders. Existing mathematical models indicate a number of influential factors on measurement accuracy. The paper presents the measurement procedure performed on a belt feeder in laboratory conditions, with variable speeds and belt tensions and the known raised position of the measuring idler. Based on the obtained results, appropriate conclusions were made about the influences on calibration and measurement accuracy.

3

Gearbox faults feature selection and severity classification using machine learning

Zuber Ninoslav, Bajrić Rusmir

Eksploatacja i Niezawodność

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2020

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Vol. 22, no. 4

748--756

EN

The most widely used technique for gearbox fault diagnosis is still vibration analysis. The need for gearbox condition monitoring in an automated process is essential and there is still a problem with the selection of features that best describe a fault or its severity level. For this purpose, multiple-domain vibration signals statistic features are extracted through time and frequency domain by postprocessing of raw time signal, time-synchronous average signal, frequency spectra and cepstrum. Five different datasets are considered with different levels of fault analyzing gear chipped and a missing tooth, gear root crack, and gear tooth wear under stable running speed and load. A preliminary experimental study of a single stage test bench gearbox was performed in order to test feature sensitivity to type and level of fault in the process of clustering and classification. Selected features were finally processed using an artificial neural network classifier.