Assessment of fiber optic sensors for aging monitoring of industrial liquid coolants

Abstract

Lately the demand for in situ and real time monitoring of industrial assets and processes has been dramatically increased. Although numerous sensing techniques have been proposed, only a small fraction can operate efficiently under harsh industrial environments. In this work the operational properties of a proposed photonic based chemical sensing scheme, capable to monitor the ageing process and the quality characteristics of coolants and lubricants in industrial heavy machinery for metal finishing processes is presented. The full spectroscopic characterization of different coolant liquids revealed that the ageing process is connected closely to the acidity/ pH value of coolants, despite the fact that the ageing process is quite complicated, affected by a number of environmental parameters such as the temperature, humidity and development of hazardous biological content as for example fungi. Efficient and low cost optical fiber sensors based on pH sensitive thin overlayers, are proposed and employed for the ageing monitoring. Active sol-gel based materials produced with various pH indicators like cresol red, bromophenol blue and chorophenol red in tetraethylorthosilicate (TEOS), were used for the production of those thin film sensitive layers deposited on polymer's and silica's large core and highly multimoded optical fibers. The optical characteristics, sensing performance and environmental robustness of those optical sensors are presented, extracting useful conclusions towards their use in industrial applications. Downloaded From: http://proceedings.spiedigitallibrary.org/ on 05/27/2015 Terms of Use: http://spiedl.org/terms Proc. of SPIE Vol. 9359 93591Y-2 Downloaded From: http://proceedings.spiedigitallibrary.org/ on 05/27/2015 Terms of Use: http://spiedl.org/terms Proc. of SPIE Vol. 9359 93591Y-3 Downloaded From: http://proceedings.spiedigitallibrary.org/ on 05/27/2015 Terms of Use: http://spiedl.org/terms Proc. of SPIE Vol. 9359 93591Y-6 Downloaded From: http://proceedings.spiedigitallibrary.org/ on 05/27/2015 Terms of Use: http://spiedl.org/terms

Towards Online Ageing Detection in Transformer Oil: A Review

“…Different sensitivity responses are expected based on the choice of material, component refractive index and mode of propagation. For example, an experiment conducted by [ 61 ] for ageing monitoring of an industrial liquid coolant showed that silicon fibres exhibit more efficient behaviour than polymer fibre (when used for acidity monitoring) in terms of stability and repeatability. However, polymer fibres have better sensitivity, biocompatibility and bending tolerance [ 59 ].…”

Sensitivity Analysis of Intensity-Modulated Plastic Optical Fiber Sensors for Effective Aging Detection in Rapeseed Transformer Oil

“…The sensitivity responses of these fibers are inherently influenced by their material selection, RI, and propagation mode. A study by [20] indicated that silicon fibers, when used for acidity monitoring, demonstrated enhanced stability and repeatability compared to polymer fibers. Conversely, polymer fibers were noted for their heightened sensitivity and superior flexibility [19,21].…”

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“…Han et al present a cylinder capacitive sensor to detect changes in the lubrication oil condition of an engine lubrication system [ 39 ]. Moreover, sensors based on other electrical properties measurements have been also studied, such as Chen et al [ 40 ], Shinde et al [ 41 ] and Riziotis et al [ 42 ].…”