Critical cranes examined

In order to safely transport huge paper rolls, the Palm paper factory double-girder bridge cranes must function flawlessly. For this reason, Konecranes has closely analysed the gear oil of the cranes and used the endoscope to look deep inside the gears.

Palm has asked Konecranes to look at eight of its most critical cranes. Following the results of the oil analysis and subsequent endoscopic investigation, the maintenance experts identified a significant risk to future production and replaced one of the hoisting gears completely.

“The cranes are in use day and night,” says Sven Bohrer, electrical engineer at the Palm paper factory. “If one should break one day, the production would have to stop, or at least greatly slow down, until the problem is solved. This would cost us time and money.”

For the oil analysis at Palm, Konecranes experts took samples from the hoisting gears of the eight double-girder bridge cranes. “The samples are analysed by our laboratory, which specialises in industrial drive train analysis. Here, the lab staff compares the current state of the oil with the samples taken in 2016 and against the OEM design limits,” says Nico Zamzow, VP industrial service EMEA Central at Konecranes.

“This way, we also use trend analysis to provide the best possible picture of any change within the condition of the gearbox.” The result for Palm: Seven of the eight cranes were found to be “healthy”, as in the gear oil contained few to no foreign elements or waste substances indicating contamination or wear. However, the gear oil of the automated number 5 crane, used in the roll warehouse, was found to have a noticeable increase in its wear partial count, triggering the lab to issue a “Caution” notification on the analysis report. Nico Zamzow: “Iron particles in the oil can be an indication of increased wear and a deeper look may be required for this particular hoist.”

Following the endoscopic investigation, the Konecranes service experts are certain: The hoisting gear must be replaced. In addition, the cable drum, the cable drum support, the slip-ring unit, the cylinder coupling, and the motor coupling must be renewed. “Thanks to discovering the wear early on, there was no risk to safety and we were able to replace the old gear with a new one without affecting production,” explains Nico Zamzow.