In full swing: Analytical strategies for the conservation assessment of operating Industrial Heritage machinery

The condition assessment of Industrial Heritage machinery in operation is an open research subject of utmost importance for defining conservation and maintenance plans. The present work approaches this issue by proposing the study of Industrial Heritage machinery that includes the assessment of substrates, coatings, lubricants and operating mechanisms by applying analytical techniques currently used for heritage studies together with techniques employed in condition monitoring of modern machinery. An early 20th century steam engine from the Vale de Milhacos Gunpowder Factory (Portugal), in operation for demonstration purposes, was selected as a case study. The engine metallic alloys and coatings were studied by XRF and Raman spectroscopies, and the main properties of lubricants studied according to EN ISO and ASTM standard tests. Metallic particles present in the oil due to wear were assessed by XRF. The mechanisms were examined by gamma radiography, magnetoscopy, thermography and vibrational analysis. Data showed the use of distinct alloys according to the engine components' function similar to those reported for the same period. Green copper phthalocyanine and toluidine red identified as coatings' pigments are typical from the late 20th century and thus ascribed to a previous repair. The properties of the fresh and used lubricants are slightly different but without evidence of a significant alteration that could endanger the machine's functioning. However, the presence of metallic particles in the oil suggested the existence of wear phenomena. The engine's operating speed (51 rpm) and the vapour temperature ( approximate to 154 degrees C) attained inside the cylinder were indirectly determined. The presence of cracks on the engine structure was assessed, and possible faults that can imperil the engine functioning were analysed. The vibrational analysis of equipment in operation revealed a lack of lubrication and wear on the feed pump journal bearings. (c) 2023 The Author(s). Published by Elsevier Masson SAS on behalf of Consiglio Nazionale delle Ricerche (CNR). This is an open access article under the CC BY -NC -ND license ( http://creativecommons.org/licenses/by-nc-nd/4.0/ )